Plot Tunnel

Most RPGs and Metroidvanias are free-roaming affairs: Between the scripted cutscenes and predetermined plot points that take place at designated locations, you are free to Take Your Time, get Sidetracked by the Gold Saucer, and generally go Dungeon Crawling anywhere your current abilities allow (assuming it isn't blocked off by a Broken Bridge).

At least, until you enter a Plot Tunnel: A tightly linear, Plot-driven sequence where your usual ability to freely explore areas and perform Side Quests is denied you in favor of whatever plot-dictated events shall unfold. There are No Sidepaths, No Exploration, No Freedom within a Plot Tunnel; your only objective is to proceed straight ahead while the plot develops (and possibly twists). You will be able to return to your usual, player-driven exploration routine only after you've exited out the other end, though things might not be quite what they used to be.

In rare cases, a Plot Tunnel can make a game Unwinnable if you enter the tunnel without the capabilities needed to get through its challenges and are unable to gain the necessary power inside it.

Can be considered a gentle form of Railroading, in that the player has no choice except to Follow the Plotted Line. When a Plot Tunnel occurs during the final act of a game, it becomes the Point of No Return. Contrast Plot Detour, when you cannot proceed with the plot without taking on a sidequest that is unrelated to the main plot. Compare One-Time Dungeon; often the two tropes overlap, with a Plot Tunnel area that you can't return to after you've completed it.

Note that since dungeons come in all shapes, sizes, and lengths, a general guideline for identifying a Plot Tunnel is that it should be at least two dungeons long, with no ability to access the Hub Level or use your Warp Whistle in the meantime.

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Examples:

• In The Adventures of Rad Gravity, after traveling through the second Star Gate, your ship runs into an Asteroid Thicket, stranding you there until you find the spare parts in a nearby derelict ship.

• In Baldur's Gate II there is one mid-game, starting in chapter 4 by going to Brynnlaw (the tunnel entrance), proceeding through Spellhold and optionally the Sahuagin city, and ending in chapter 5 by leaving the Underdark (with the tunnel exit being a literal one). After this the game areas re-open again. Fortunately, the Underdark comes with plenty of new side quests of its own and its areas can be backtracked later (not so for Brynnlaw and Spellhold).
• Batman: Arkham Knight: Unlike the games before this one in the series, where you could still play side missions during plot segments if they happened to be on your path, Knight actively prevents you from selecting side missions to play in several spots:
  • The ACE Chemicals sequence.
  • The Cloudburst sequence, with one small exception: a few Watchtowers that are higher than the gas cloud are still available.
  • The raid on the Arkham Knight's HQ.
• In Breath of Fire IV, near the end of the first chapter you set foot on the Evil Empire's homeland for the first time to search for your missing princess. Although you do have access to the Overworld Not to Scale, you have no Warp Whistle at this point, and the only location you may travel is a nearby town and waterway, which you use to sneak in to the Imperial base in search of the princess. This ends with the party being discovered, captured and deported as the game begins Chapter Two.
• Bug Fables: The Honey Factory goes on lockdown soon after entering it, preventing leaving it until the chapter's boss is defeated. This also means that the Bubble Shield ability unlocked here cannot be used to access some of the side areas until after the chapter, unlike most overworld abilities. The game implicitly warns the player that the Honey Factory will be a Plot Tunnel and suggests storing up on items before entering, but since the protagonists could not possibly know that the factory will go on lockdown, Vi instead says that the tour is long and won't let anybody leave in the middle of it.
• Cave Story has a long sequence in the middle of the game, proceeding immediately from the Storehouse Boss Battle, taking you through the Labyrinth and Waterway and some major plot twists. There is very little room for exploration here, and the teleporters that would ordinarily return you to Player Headquarters are for the moment broken or only connecting with each other.
• Child of Light has one from when Aurora enters the Magic Mirror and is imprisoned in the Forgotten Tower, until after you defeat Cordelia/Crepusculum.

• In Dragon Age: Inquisition, almost all main plot missions are like this except the start of the Grey Warden arc, which takes place in the open world. Each of them takes place in a long, isolated area, and you cannot return to your base or explore the open world until you complete the mission.

• EarthBound (1994) has a mild example. Once you take the Runaway Five van to Threed, you cannot return to Twoson or Onett until you defeat Master Belch.
• Edge of Eternity: When you set off to find Alpharius on the Kaladaan Coast, a message box pops up, saying
  A sense of foreboding fills our heroes. If you step further, you will not be able to go back for a good while. Do you wish to proceed?
  Yes/No
• The Elder Scrolls V: Skyrim has a few, though they tend to be short. One is the two-part Forsworn sidequest in Markarth, which involves you being incarcerated and all your gear confiscated for the duration, until you either help Madanach escape or kill him and escape on your own. Another is part of the Main Quest where you infiltrate the Thalmor embassy, cause some distractions, sneak past (or kill) some guards, recover some intelligence, and rescue some people before you can return to normal freeform gameplay. The Forgotten Vale from Dawnguard is also an example until you open all the waypoints.

• Most of the DLC's to Fallout 3 and Fallout: New Vegas, with the exception of Broken Steel, Point Lookout and Lonesome Road, lock you in until you complete their quest line.
  • Point Lookout itself does this with the highly linear Calvert Mansion and Sacred Bog sequences. The former magically locks the doors behind you once you enter the west wing, preventing you from leaving until you finish the quest. The latter is on a separate world map from the rest of Point Lookout, which precludes fast-travel.
  • Honest Hearts also disables fast-travelling for certain quests, including the finale, which also cancels all uncompleted sidequests.
  • In Dead Money, you can't leave the Casino until your mission there is completed, but afterward, you can freely explore the Villa before returning to the Mojave Wasteland.
  • Raven Rock from the former game also counts, as does the Project Purity battle if Broken Steel is installed, which is otherwise a normal Point of No Return.
  • During the Reilly's Rangers sidequest, the Statesman Hotel entrance is one-way only, forcing you to fight onward through numerous floors infested with Super Mutants until you reach the rooftop and fix the elevator that leads back to the ground floor.
  • In Fallout 4's Cambridge Polymer Labs sidequest, you are Trapped in Containment until either you complete the pre-war scientists' unfinished Piezonucleic Power Armor experiment, or hack the Director's Master-locked terminal to override the lockdown.
    • When you first teleport to the Institute, you're locked into a linear sequence until after completing "Institutionalized" and obtaining the Pip-Boy relay from Dr. Li, which allows you to teleport to and from it at will.
    • Automatron has one in the Fort Hagen Hanger after you retrieve Jezebel, where the door you entered through locks and you have to take a constrained path that includes fighting Those Two Bosses and several strong Mecha-Mooks.
• Final Fantasy IV has so many tunnels it might as well be a submarine. Every time you get access to the Global Airship, continuing your quest throws you into one of these. These are the "surface" points:
  • When you first get the airship^note From that point you have free access to the overworld up until you enter the volcano, which traps you in the underworld
  • After you get out of the underworld the first time^note Though you lose access to the underworld in the process, so from a certain point of view you're swapping one tunnel for another. Then you lose access to the overworld once you complete the Elban Cave / Tower of Babel segment and fall down the trapdoor, though this finally opens up most of the underworld.
  • After you get out of the underworld the second time. ^note At this point you have access to almost every part of the world except the final dungeon; this ends when you meet FuSoYa in the palace on the moon. After meeting him, trying to return to Earth will start the inescapable Giant of Babel dungeon, so you're locked on the Moon until the Giant of Babel is defeated.
  • After completing the Giant of Babel.^note After this point you are free to do whatever you want; there is no Point of No Return after this quest
• The gate to the Land of the Espers serves as a Tunnel Entrance in Final Fantasy VI. You come out of the (plot) tunnel shortly before the major Point of No Return. The Opera House could also count as it locks Gau out of the Veldt until just before the aforementioned gate.
• The Northern Continent serves as one in Final Fantasy VII, though you still have a chance to slog your way back the long way until you start snowboarding.
• Final Fantasy X: Reaching the Macalania Temple counts as one. Seymour is outed as a villain (but really, who was fooled?^note Except Wakka), the party are marked as traitors for defending themselves, and after a mass-Party Scattering event that leaves you without Yuna, the declaration of war between the Al Bhed and the Guado, and the genocide of the former, things are looking pretty bleak. And then you enter into Bevelle to retrieve Yuna... Quite appropriately, you exit the other end of the tunnel at the point where the world is opened up a bit.
• Early on in Final Fantasy XII, Vaan sneaks into the Dalmascan palace through the Garamsythe Waterway. This leads to a series of events in which he meets up with sky pirate Balthier, the party is captured and imprisoned in Nalbina Fortress, escapes through the Barheim Passage and must head back to Rabanastre (the Hub Level) from the eastern desert.
  • It's noteworthy that this game typically warns you if you're in the middle of a Plot Tunnel when saving, advising you to make a separate save file so as to avoid getting stuck.
• Final Fantasy XIII is rather infamous for putting the player through a Plot Tunnel that starts with the Prolonged Prologue (two chapters long) and ends by Opening the Sandbox... eight chapters after that. That's right, you spend ten chapters out of thirteen with No Sidepaths, No Exploration, No Freedom. The base was slightly broken about that, to say the least.
• Final Fantasy XIII-2 contains a tunnel late in the game, when Noel and Serah are intercepted in the Void Beyond by Caius and trapped in a Lotus-Eater Machine, locking them out of Historia Crux until they escape from their respective dreams. Thankfully, the game gives you ample warning beforehand.
• Final Fantasy XV has a habit of faking the player out with moments that appear to be point of no returns, but they're often just chapter-long plot tunnels that give you plenty of breathing room after they've concluded to grind, complete side quests, etc. The ability to return to the past makes this true even after the story's definitely progressed past a point of no return.
• Final Fantasy Tactics has a few of these every chapter starting with chapter 2. You will complete a battle, then automatically get a chance to save, even though normally after battle you go back to the world map. In these sections, another battle will immediately follow, with you only having time to change your team's loadout, but no chance to replenish items or anything. But woe be it to those who don't keep a back up save, as many of of the hardest fights in the game take place after these save points. Hope you kept a backup for the Wiegraf fight!
• Fire Emblem Engage has two of these, which involve playing two chapters back-to-back without being able to switch your deployed allies or return to the world map in between. Thankfully, the game will warn you when you're about to enter the tunnel. Each tunnel contains a major Wham Episode: Chapter 10-11 reveals that Veyle is Sombron's daughter and Lumera's murderer, features Sombron's revival, and results in the loss of all your Emblem Rings, while Chapter 21-22 has Alear jump in front of Veyle to block Sombron's attack, dying in the process and causing their temporary revival as a Corrupted before they become an Emblem themselves.

• "The Fate of Tsushima", the last mission of Act 2 in Ghost of Tsushima not only locks you into a long multi-stage Tale, but several more Tales afterwards, during which your horse is killed and you won't be able to fast travel back to the first two islands until you complete the first major Tale of Act 3 and reunite with Jin's allies.
• In the first Golden Sun, it's impossible to go through Mogall Forest in reverse, so once you've left it the only way back to earlier areas is to pass through Lamakan Desert.

• In Haven (2020), after their first night on Source, Yu and Kay are cut off from the Nest by a tremor splitting the Islet Guyame in two, forcing them to find an alternate route back via flow bridges between several nearby Islets. Later on, after the vidchat with Yu's mom and an argument, Yu runs off, and the player controls the two separately until they are able to get back together, putting all sidequests, crafting and exploration on hold for the time being. The player is also unable to summon Birble at this time.
• Hollow Knight
  • Crystal Peak has one that can be avoided if you save up enough Geo to buy the Lumafly Lantern. If, after acquiring the Desolate Dive, you take the upper entrance to Crystal Peak but don't have the Lantern, you won't be able to see the mechanism for the Cash Gate back to Forgotten Crossroads, and will just have to press on through the dungeon until you either reach the Resting Grounds, which extend the tunnel further but have a Stag Station at the end, or obtain the Crystal Heart, which unlocks a passage back to Dirtmouth.
  • The first visit to the City of Tears also qualifies if you enter through the main gate, which locks behind you, so you can only exit once you either obtain the aforementioned Desolate Dive from the Soul Master, which allows you to bypass the gate, find a Simple Key to unlock the Royal Waterways, which leads to another Door to Before back to Fungal Wastes, or pay to unlock the Stag Station or the Elevator to Before back to Forgotten Crossroads. All of these options require a fairly long and linear roundabout trip from the entrance.
  • A mandatory one occurs in the Beast's Den sub-area of Deepnest, where the residents lure you into sitting on a bench that traps you and you have to escape from a labyrinth guarded by Demonic Spiders to reach Herrah the Beast's resting place and the exit.

• In Knights of the Chalice, there are several dungeons in where you end up having your exit blocked when reaching a certain point, and the only way to proceed is by beating a specific encounter. It also usually won't allow you to rest when that happens, which means crafting items and conserving spells are almost requirements.
• After Opening the Sandbox in Knights of the Old Republic II: The Sith Lords, there are several occasions where the player is denied the ability to return to the Ebon Hawk and the rest of the galaxy until you finish up your business on the planet.
  • The biggest Plot Tunnel is Nar Shadaa, which automatically sets you on a one-way trip to the planet's endgame after you've earned the attention of the Exchange. When this happens, you're forced to go through Jekk'Jekk Tarr, a duel between Mira and Hanharr, the Exchange base, and eventually Goto's Yacht, all while swapping between the Exile and several party members.
  • When you return to Dxun after Onderon breaks out in civil war, the Exile takes a party with them to end the civil war, while a side party investigates Sith activity on Freedon Nadd's Tomb. At least you have control over when to trigger it and which party members to field.

• The Legend of Zelda:
  • In The Legend of Zelda: Ocarina of Time, when you first draw the Master Sword and become an adult, you have no way of becoming a child again even if the player already knows how, since Sheik is blocking the pedestal that the sword needs to be returned to. Only after finishing the Forest Temple does Sheik explain the process and then move aside, allowing you to travel back to Link's childhood as you wish.
  • The Legend of Zelda: Oracle Games each feature an example:
    • On visiting Subrosia from the Mt. Cucco portal in Seasons, your Roc's Feather is stolen from you by a pair of kooky brothers. You need to trail them to their hiding place in a forest to recover it before you can go anywhere else, since all paths out of the small area you're in require jumping over pits and lava.
    • In Ages, Link's journey to the third dungeon leaves him shipwrecked on a small island inhabited by some kleptomaniac Tokay. After recovering your stolen gear and finishing the dungeon, Moonlit Grotto, you meet up with a friendly Dodongo named Dimitri who can swim you back to the mainland.
  • In The Legend of Zelda: The Wind Waker, your voyaging across the sea is pretty limited for the first couple dungeons. Even after obtaining your own boat to sail, the King of Red Lions will only let you travel from Windfall Island directly east to Dragon Roost. Once you reach Dragon Roost, he won't let you leave until you have what you came there for. And once that's accomplished, he'll only let you sail either directly west back to Windfall or directly south to the next island, the Forest Haven. Only once you've finished with the Forest Haven does the rest of the world open up to you, since the routes between islands are a lot less lineated after that.
  • The Legend of Zelda: Twilight Princess features a few instances in which Link is trapped as a wolf, which prevents him from using his items and interacting with other characters.
    • Each time you enter the twilight, Midna delights in reminding you that you're stuck there until you find a portal you can use to leave. In the case of Lanayru Province, doing so involves a lengthy process of circumnavigating Hyrule Field, jumping down into Lake Hylia, using a bird to fly upriver, and then climbing to the tippity-top of Zora's Domain. And even when you do find a portal, you're still trapped as a wolf until you restore the light spirit of whichever province you entered, leaving little else that can be done in the meantime anyway.
    • You're trapped as a wolf for the final time after finishing the Lakebed Temple. You can't warp between places initially, and until you've gone to see Princess Zelda for advice, you can't even leave the vicinity of Castle Town. Afterwards, you'll be able to warp again, although you still have to go back to Faron Woods and find the Master Sword in order to become human.
  • The Legend of Zelda: Skyward Sword has two.
    • The first is on your initial descent into Faron Province. You're briefly stuck at the Sealed Grounds until you investigate the pit, enter the Sealed Temple, and learn of your mission from the old woman inside. Exiting the temple through the side door takes you to a Goron who explains the process of using Bird Statues to return to the sky, after which said statues activate and can be used for the first time.
    • Later in the game, there's the Eldin portion of the Song of the Hero questline. On descending to Eldin Volcano, Link is caught in a sudden eruption and has his gear stolen by Bokoblins. The player has to sneak past them and recover Link's items in order to meet with the Fire Dragon, all while the the turbulence in the atmosphere caused by the eruption prevents him from fleeing back to the sky to regroup.

• The Horizon and the Collector Ship mission of Mass Effect 2 count, since both will block all exploration and side-quests after recruiting the fourth and the seventh squad member, respectively, until you complete them. In this case, the Plot Tunnel begins in the respective previous mission, though you don't know that on your first play-through.
  • The Mass Effect 3 DLCs "Omega" and "Citadel" operate like this, as do the "Overlord" and "Arrival" DLCs for 2; each is comprised of several distinct levels, but once the player begins, they have to finish the rest of the DLC before returning to the Normandy.
• Mega Man:
  • After defeating the first set of Robot Masters in Mega Man 7, you're forced into a boss battle against Mash, a robot clown. You cannot revisit the previous stages or go to Auto's shop to gather E-Tanks during this time, and if you have trouble defeating him, well...
  • Mega Man 8 sends you to Duo's stage after defeating the first four Robot Masters, and like 7, you cannot use the shop during this time.
  • A particular frustrating example happens in Mega Man Legends. After opening the Main Gate in the Clozer Woods Sub-Gate, leaving the dungeon results in a long battle on board the Flutter against several enemies and then two bosses in a row. Making this extra aggravating is the fact you get no warning about this, and the fact that the Flutter has its own life meter; if it's shot down, it's an instant Game Over, and there's no way to heal it at all. It's very possible to not prepare and save, and since you're cut off from town and all side-quests until after the fight, this could very well result in an Unwinnable situation and force you to start the whole game over again (after about four or five hours in for an average player).
  • In Mega Man Zero 4, after defeating four of the eight bosses, the human settlement becomes under attack and Neige is captured, and you're forced into two stages in a row, the first of which ends with a boss battle against Kraft. If you haven't been gathering Sub-Tanks, good luck.

• Octopath Traveler II: Osvald's story has him framed for murder and sentenced to The Alcatraz. His Great Escape takes up his first two chapters. That means that chapter 1 leads directly into chapter 2, and you do not get access to the overworld until you're done with both. If he's not your main character, the game directly warns you that playing his chapters might take a while upon encountering him.
• Ori and the Blind Forest, in addition to the Point of No Return at the Final Dungeon, has several mid-game plot tunnels:
  • Gumo's Hideout, in which after falling down a trap door, you follow a long linear corridor to learn the Double Jump so you can ascend a Spikes of Doom-lined shaft and navigate a Corridor Cubbyhole Run of falling rocks to retrieve the Water Vein and escape.
  • The Ginso Tree Escape Sequence and the following Disconnected Side Area of Thornfelt Swamp, until you learn the Ground Pound and use your newfound ability to defeat two Rams and unblock the path back to the main hub.
  • The Mobile Maze sequence in the Misty Woods, which starts once you collect the first Key Stone.
  • The second half of the Forlorn Ruins^note Once you place the Light Vessel in its pedestal, you can't return to the first half, or, in the Definitive Edition, access the Spirit Well to warp out., followed by its Escape Sequence and the stealth-based escape from Kuro's Nest.
• In Ori and the Will of the Wisps, once Ori finds Ku in the Silent Woods, the two are thrust into an Unexpected Gameplay Change gauntlet of puzzles and One-Hit Kill traps utilizing rather awkward flight controls. During this sequence, the Warp Whistle is disabled, and attacks are limited to the Flap and Spirit Arc. Fortunately, the sandbox is fully open for the player afterwards.

• In Pathways into Darkness, after entering the one-way door on "Warning: Earthquake Zone", there's nowhere to go but downwards until after clearing "Okay, Who Else Wants Some?". Better not have missed the nuclear device or any other critical items, or you'll find yourself up a creek without a paddle, as said one-way door also prevents you from returning to the lower levels.
• As Persona games chiefly take place in one city and entries from Persona 3 onwards work on a calendar system with a single dungeon per month, Plot Tunnels in these games are not long sequences of dungeons but rather unusually long sequences of story days:
  • Persona 4 has a unique one that starts with the second term finals (which start on November 28 and end on December 3) and lasts until December 8th. There are no dungeons or fights during this time, but you are forced into a long sequence of story cutscenes where the murder mystery plot comes to a head, and you need to deduce the identity of the killer to avoid a Non-Standard Game Over. Only after this is all over are you allowed to go to dungeons and work on Social Links again.
  • The third semester of Persona 5 Royal starts with a sequence from January 2 to 12 where you're forced into the new Palace three times, twice with a less-than-complete party since the Palace's ruler, Maruki, has turned the world into a Lotus-Eater Machine, which has entranced the rest of the Phantom Thieves: once with Joker, Akechi, and Kasumi; a second time with just Joker and Akechi after Kasumi turns out to actually be Kasumi's younger sister Sumire—who Maruki overlaid Kasumi's personality onto to treat crippling Survivor Guilt—and is taken hostage by Maruki; and a third time with a full party. In between the first and second visits, you have to visit and talk to the rest of the Phantom Thieves to snap them out of the dream world, one a day, with fast travel disabled.
• There are a few sequences in the Pokémon Mystery Dungeon series where you must progress through multiple dungeons without access to the usual shops, the Hub Level, your mission list, or being allowed to recruit new team members.
  • In the first installment (Red and Blue Rescue Team), at one point your party is framed for the disasters plaguing the world and run out of town on a manhunt, leading to a Fugitive Arc that lasts for five dungeons (including two Boss Battles) before the matter is resolved and you are allowed to return home.
  • In the second installment (Explorers of Time and Darkness), the Guild makes an expedition to Fogbound Lake (a total of four dungeons and one Boss Battle). Later, an unexpected trip to the future turns the entire plot upside down across a sequence of four dungeons; even after returning to the present time, you must progress through an additional dungeon before you are allowed to return to the Guild and resume your usual routines.
  • The entire latter half of Pokémon Mystery Dungeon: Gates to Infinity ends up being this way, as once you return from the Great Glacier, you'll eventually be forced to go on an adventure to rescue Munna after a few days pass, and once you get back from that ordeal, are forced to begin your final adventure to save the world. You can, however, use the new Companion Mode to complete missions at your leisure in the middle of these adventures, though without the aid of your hero, partner, and whoever else is involved.
  • Pokémon Super Mystery Dungeon is much more notorious about this, not even letting the player take their time to grind if the dungeon proves too tough.
• Pokémon Red and Blue:
  • There's one early on: After you leave Mt. Moon, there's a ledge with no ladders or stairs going back up. Once you jump down, you're effectively locked out of that area until you're able to enter the third Gym. The bad part is that, though there is a shop and Pokémon Center right after, you may have to rely on low-level Com Mons for leveling up to deal with Misty and Blue.
  • In the GBA remakes, FireRed and LeafGreen, after beating Blaine, Bill shows up and offers to take you along on an errand to the Sevii Islands. If you accept, you are committed; you have no access to your box storage until arriving at Three Island and no ability to leave the islands until the sidequest is complete, although you are given a Pokémon Center and a shop with some very basic amenities.
• After calming the final Lord in Pokémon Legends: Arceus and reporting to Kamado as usual, the situation with the rifts escalates tremendously, leading to the player getting expelled from Jubilife Village the next day out of suspicion. The player can't return to Jubilife until they've visited each member of the Lake Trio and created the Red Chain, at which point Cyllene reinstates them into the Galaxy Team due to Kamado having already left for the Temple of Sinnoh. Until then, the Ancient Retreat serves as the hub area, Cyllene's Abra becomes the waypoint for accessing the pastures, and Volo and clan members (depending on which clan the player chose for assistance) sell supplies and manage camps; all other services are unavailable.
• [PROTOTYPE] has a variation: After completing one boss fight, your combat-transformation abilities are disabled. You can still free-roam, and you're not exactly helpless, but the (massive) restriction of your freedom for the next handful of story missions tends to have players make their own Plot Tunnel to get their hammerfists back.
• Rakenzarn Tales: Kyros has an exclusive chapter on this route called the Extra Scenario which follows his friend Mayu as she gets sucked into Rakenzarn and has her own adventure in a separate location. Once you start, you play as her party the entire time and can't return to Kyros until her chapter is complete. The game does warn you beforehand and you share any items and unused equipment. Sparing some good gear is a necessity as she doesn't gain access to a shop until at least the second part.

• Secret of Mana has a few. Most notable are the Northern Forest which you reach after beating all the first continent's dungeons and bosses and gotten through the Earth Temple's Fire Gigas, and the other one when you launch onto the Empire's main island, which is comprised of South City and North City, with no way back, and only a Sewer Level between the two, and the Disc-One Final Boss.
• In Shin Megami Tensei IV, at the end of a major split and potentially a boss fight, Flynn, Jonathan, and Walter are all forced into two different dimensions back to back. You cannot return to the main setting until you beat the main boss of each world, avoid the bad ending, and clear another dungeon with four more bosses. If you do get the bad ending, it's a Point of No Return. Moreover, avoiding the bad ending also triggers the alignment lock, so the tunnel "surfaces" into one of three mutually exclusive lanes.
• Suikoden V contains a variant of this. During certain plot events, some allies cannot be sought and recruited.
• Super Mario Bros.:
  • In Paper Mario, Mario gets accused of killing Mayor Penguin at the beginning of Chapter 7. At that point, you are unable to leave Shiver City until you've cleared your name.
  • Paper Mario: The Thousand-Year Door has a lot of tunnels starting with Chapter 4:
    • Halfway through Chapter 4, your name gets stolen and, without it, you can't use the pipe leading back to Rogueport.
    • Chapter 5, you're shipwrecked on an island and don't get another boat until you've beaten the chapter.
    • Chapter 6 is entirely spent aboard a moving train.
    • Chapter 7 starts by blasting you off the moon, and you can't return to Rogueport until you find a teleporter in the villain's hideout.
  • Super Paper Mario continues the trend of these sections popping up in Chapter 7, when Mario is sent there prematurely and separated from his party members. You have to reunite with Luigi, find a missing NPC, and get one of the Pure Hearts restored before you're allowed to go back to Flipside, and you can't advance to the rest of the chapter until you revisit it afterward through the proper channels.
  • Mario & Luigi: Bowser's Inside Story does this by presenting multiple points where Bowser is suddenly rendered unplayable, requiring the Bros to undertake an objective from the inside, which could last as little as the span of a minigame or as long as an entire dungeon.
  • In Mario & Luigi: Dream Team, you have to finish Mushrise Park and Dozing Sands before the bridge back to Pi'illo Castle is repaired. Later on, when the heroes visit Dreamy Mount Pajamaja, the portal to the real world closes unexpectedly, trapping them there until they ascend the mountain and fight the boss at the peak in order to open it again.
  • The first two Mario Party games of all things have this in some form. In the first Mario Party, you will unlock the Eternal Star board once you have accumulated 100 Stars in the bank. Once this happens, you will be unable to play on any of the other boards until you have played through Eternal Star at least once, the reason being that Bowser has stolen all of the Stars you've saved up. You also cannot purchase anything at the shop or change up your items at the bank during this time. Similarly, in Mario Party 2, you will unlock Bowser Land after playing on each of the other boards at least once. When this happens, Bowser will kidnap Toad and leave you with no choice but to play on Bowser Land at least once in order to rescue him.
• Shanghai.EXE: Genso Network:
  • When Alice and Shanghai are separated, like when infiltrating Border Concern, then Shanghai can't leave the area until the plot is resolved and they meet up again.
  • The ROM Comp area is locked into since there's a in-universe time limit to shut the computer down.
• Tales of Vesperia has this in the second act. Once the party boards Heracles, the player has to stick to the plot until Estelle is rescued from Alexei and Zaude arises. During this time, Ba'ul is put out of commission and the Fiertia damaged, leaving the player stuck on Ilyccia until the sequence is complete.
• Trials of Mana has two, both in the Laurent region.
  • Once you defeat Bil & Ben and chase Belladonna out of Citadel Laurent, the regular ferryman will be unavailable, replaced instead by the Ghost Ship. After sinking it and escaping Beuca Island, you return to the game at the beaches of Maia, and a visit to Valsena gets you the Ferry Flute you need to open most of the game world.
  • Once you find Flammie at the summit of Laurent's peaks, you are shunted straight to the Sanctuary of Mana and cannot leave until you get the Sword. You pick up the Wind Drum you will need to leave at the same time, though, which opens up nearly the entire rest of the world.
• A Very Long Rope to the Top of the Sky: Storming Avishun Castle locks the party in the castle area until they finish storming the place by beating the enemy force's commander at the top of the castle.
• Two are present in Warframe, both relating to main quests.
  • The first tunnel is during The War Within, where upon revealing the Kuva Fortress, you are given a prompt to either proceed to the location or to extract and re-equip. Continuing on ends up locking you in the introductory level of the Kuva Fortress, a vision of a mountain pass where you unlock your Operator’s powers, and a boss fight against the Elder Queen and her Kuva Guardians and Tenshinuntil you steal the Queen’s scepter, deal with her, and extract.
  • The second combines this trope with Marathon Level with The New War, as upon selecting the quest you are given a Content Warning that warns you that the quest will take roughly a couple hours to complete and that you really should get ready to do it in one sitting before letting you cross the Point of No Return.
• Xenoblade Chronicles 1:
  • The game has a brief one. Between the events at the end of Agniratha and the final battle with Egil at the Mechonis Core you can't Skip Travel at all. You still have access to the Central Factory and Agniratha, but nowhere else, and if there's anything in either area you want to take care of you have to walk there yourself. After the Core you have access to the Bionis again, but the Mechonis is gone for good.
  • There are two more minor examples, around the first plot visits to the High Entia Tomb and the Fallen Arm. The common element is the POV switching between different groups of a scattered party, suggesting the restriction has more to do with careful management of Event Flags than actually trying to railroad the player.
• Xenoblade Chronicles X is riddled with examples. Only one Story or Affinity mission can be active at once, and when activated, the storyline within has to be completed; additionally, most of them bolt at least one person into a party slot for the duration. Save when an Affinity mission is active? You're not advancing the plot until that sidequest is done. Downplayed in that the entire game world is still available to you and any remaining party slots can be shuffled as you please, making the tunnels more narrative than gameplay... with one exception: one chapter of the story locks the player into the primary city for the duration, since the whole point of the chapter is that the place is under siege and nobody can get out.
• Ys series:
  • In Ys III: Wanderers from Ys, Adol is captured shortly after entering the Ilberns Ruins and cast into the Lava Zone, where to obtain the item required to cross the lava river to the exit, you have to run a gauntlet of firebirds and lava waves, then defeat a difficult boss.
  • In Ys V: Lost Kefin, Kingdom of Sand, the Xandria occupation, which starts once you cross the Bridge To Before back from Felt, railroads Adol through a linear sequence of events leading to a battle with Adeptos Dorman, followed by an Escape Sequence. Lord help you if you're underleveled.
• Normally, Zero Time Dilemma lets you pick any fragment of the story to watch/play at your leisure, in any order you want, but not always. Sometimes the game removes all fragments from the menu except one, and will stay that way until you complete it. These fragments are usually Wham Episodes.

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