The party wakes up in the morning, only to realize that the hero has slipped away in the night and is gone. "Oh damn, he went alone" ensues, as it's obvious the hero went on a dangerous solitary errand - or worse yet, went to fight the Big Bad alone.
This trope covers all kinds of important sneaky departures on behalf of major characters.
It's an unplanned (or is it?) one-man variant of Let's Split Up, Gang!. The hero might just value their freedom, despite being a good team player so far. Maybe This Is Something He's Got to Do Himself, or just wants not to endanger the party, or not to be hindered by them. Additional points for a Heroic Sacrifice, where he did it to win the More Hero Than Thou argument in advance, not so many if we have a FaceHeel Turn, but even more points for proving to be a Fake Defector. After all, sometimes In the End, You Are on Your Own. Often indicates an upcoming Duel Boss.
In RPGs this might lead into a "follow the splitter" episode, or a Solo Sequence where the player gets to control the splitter. If the splitter is a Guest-Star Party Member, they might just leave with very valuable equipment on them.
- In Digimon Adventure 02 the DigiDestined set out to bring down the Digimon Emperor. T.K. and Cody abandon their camp before the others wake up, so they can search for the Emperor's base by themselves and save oxygen for the rest of the team, cutting the wires around the door to make sure no alarm sounds.
- Clash of the Titans (1981). While on the journey to Medusa's island, Perseus and his soldiers take off in the middle of the night, leaving Andromeda behind (and Ammon to look after her). Perseus doesn't want Andromeda to be present when the big fight with Medusa occurs because of the danger to her.
- Conan the Barbarian (1982). Conan sneaks off on his mission of revenge rather than stay with Valaria.
- In the first installment of Harry Potter and the Deathly Hallows, Harry attempts to make one from the Burrow, deciding (as usual) that he doesn't want to put anyone else in harm's way. Fortunately, Ron stops him and talks some sense into him.
- The Fellowship of the Ring. Frodo splits, though is soon followed (and joined) by Sam.
- In Azure Bonds, a Forgotten Realms classic, Alias runs on her own into the besieged Yulash and ends up freeing Moander. Later, Akabar leaves Olive's company in a similar fashion, invisible.
- The Belgariad. At one point, some of the heroes sneak out early in the morning and leave a note. Most of those they left behind are not impressed.
- The Lion, the Witch, and the Wardrobe has Edmund, who sneaks away from the beavers' house to join the White Witch.
- Happens quite often in Warrior Cats.
- In Into the Wild, Yellowfang sneaks away from ThunderClan camp to chase after Clawface, who she deduces has stolen ThunderClan kits. Firepaw, Ravenpaw, and Graypaw sneak away to chase after her, and so that Firepaw can fake Ravenpaw's death.
- In Fire and Ice, Tigerclaw claims to have found evidence of an invasion that the Clan leader Bluestar needs to see. (It's actually a trap he set to kill Bluestar so that he can take over.) However, Bluestar is too sick to go and see, so Fireheart's apprentice Cinderpaw offers to go instead. Fireheart forbids her from going, but she sneaks out of camp anyway and walks into Tigerclaw's trap, causing her to get hit by a car and break her leg.
- In Fire and Ice and Forest of Secrets, Graystripe constantly sneaks out of ThunderClan camp so that he can meet with his love interest Silverstream. This is necessary, as they are in a forbidden relationship.
- At the beginning of Forest of Secrets, Fireheart and Graystripe sneak away after a Gathering to meet with Ravenpaw so that they can find proof that Tigerclaw murdered Redtail. They later sneak away from ThunderClan territory into RiverClan to find more proof, and eventually to deliver food to the starving Clan.
- In Rising Storm, Cloudpaw sneaks away from ThunderClan to get food from humans. Unfortunately for him, this leads to him getting kidnapped.
- In A Dangerous Path, after Bluestar refuses to make them warriors, Swiftpaw and Brightpaw sneak away from the camp to fight the dogs and prove their valour. Swiftpaw ends up dying in the fight and Brightpaw gets half of her face ripped off.
- In The Darkest Hour, it's revealed that Darkstripe has been sneaking away from ThunderClan camp to meet with Tigerstar and give him intel on what ThunderClan is up to.
- The New Prophecy begins with a cat from each Clan getting an omen telling them that they need to go on a journey far away from the Clans. Since they can't let their Clanmates in on this, they have to sneak away from the Clans and meet up together for the journey.
- In Twilight, Leafpool and Crowfeather sneak away from their Clans to meet up, and eventually run away with each other. Since they didn't tell anyone, their Clans each think that they went to the other Clan.
- Dark River is basically sneaky departures, the book. First, Lionpaw and Heatherpaw are constantly sneaking away at night to meet each other. Then, Hollypaw sneaks away from ThunderClan camp and goes to RiverClan to find out what the huge problem impacting them is. Then, a battle starts when three WindClan kits sneak away from their Clan to explore the tunnels they heard about and WindClan thinks they were kidnapped. In order to stop the battle, two separate groups composed on Lionpaw, Hollypaw, and Jaypaw, and Breezepaw and Heatherpaw sneak away to find the kits.
- The plot of Dawn of the Clans is kicked off when Jagged Peak sneaks away from the tribe to join the Followers of the Sun Trail and find a new home, forcing Gray Wing to head after him so that he can keep him safe on the journey.
- In By the Sword mercenary Kerowyn abandons her Herald lover because she knows the sword she carries is attracting pursuit. She doesn't escape unnoticed (his Companion asks her just what the hay she's doing), but he lets her pass when he realizes she's being More Hero Than Thou.
- In the first Wings of Fire book, Glory appears to do this...but it turns out to be a trick she and Tsunami made up to show Clay that his Innocently Insensitive nature can be hurtful sometimes.
- In Ollie's Odyssey, Billy sneaks out after bedtime to find Ollie.
- In Agents of S.H.I.E.L.D. Season 2, Episode 5, Raina meets with Coulson and tries to blackmail him into sending Skye to a certain address, where Skye's father is waiting. Coulson had already planned for it and neutralizes her threat against him, but Skye sneaks away anyway and goes to the address Raina gave.
- The Goodies: Graeme does this in "Bunfight at the O.K. Tea Rooms", sneaking off to register the clotted cream claim while the other two are asleep. Tim and Bill spend some time talking to the Cardboard Pal he left in his place before they realise anything is wrong.
- Buffy the Vampire Slayer. After a night with Spike (apparently non-sexual), Buffy sneaks off to confront Caleb, leaving a letter in case she doesn't come back.
- Final Fantasy
- Final Fantasy VII
- Aeris leaves the party and gets killed by Sephiroth.
- Cloud attempts it early in the game, but Aerith meets him at the entrance to the next Sector.
- Adelle does this late in Final Fantasy Tactics A2.
- Over in Final Fantasy: The 4 Heroes of Light, it seems inns exist 50% to regenerate health and actions, 50% so heroes have somewhere to skulk out of early in the morning because 4 Heroes is basically Let's Split Up, Gang!: The Game. Junita in particular falls victim to this ploy from both the male heroes, two towns in a row.
- Final Fantasy VII
- Sagacious Zu in Jade Empire, around the time you infiltrate the Lotus Assassin headquarters, a decision he advised against.
- Zelos does this on a few occasions in Tales of Symphonia, including the Tethe'alla Base and Flanoir. He's actually a spy for Cruxis and the Renegades.
- In Professor Layton and the Unwound Future, Layton does this and when he comes back, it's actually Don Paolo in disguise, and so does Luke later on due to being upset by his father planning to move, separating him from Layton.
- Pinocchio in Kingdom Hearts: Chain of Memories. While Gepetto says he's happy as long as Pinocchio is around, Pinocchio blames himself for them being stuck inside Monstro and wants to find a way out, sneaking off to do so.
- Rudolph the Red-Nosed Reindeer: Rudolph feels he's endangering the others because his nose attracts the Abominable Snowmonster, so he leaves them in the middle of the night.
- Avatar: The Last Airbender:
- In the episode "The Awakening", Aang feels he needs to regain his honor by fighting the firelord alone, and so he sneaks off the ship that the gang is currently hiding out on - though they find him and join him, leaving the ship behind, by the end of the episode.
- Aang unintentionally does it again in the end of the same season. It's only unintentional because the lion turtle has him under some sort of spiritual trance, but the rest of the group thinks he's doing it purposely. This time, they don't follow and instead carry out their own tasks.