The present and future Justice Leagues fight the gang of Jokerz, who have been augmented by cybernetic enhancements. The battle goes badly enough that the future Batman calls for a retreat and opens a boom tube, but his mother box gets destroyed. The heroes finally escape by confusing the Jokerz with a bright flash of light and a ring-construct maze.
They regroup in the ruins of Hamilton Hill High School, where the future Justice League has established its headquarters after losing the Watchtower and the Batcave. Static, Warhawk, the future Batman, and the elderly Bruce Wayne are the only ones left.
Future Gotham is full of buildings taken from various historical eras. David Clinton has abandoned his earlier caution, looting historical treasures willy-nilly and taking control of the city as "Lord Chronos". Old Bruce says that while present-day Batman has traveled into the future, he himself has no memory of the event. He concludes from this that the timestream is becoming dangerously unstable. This is confirmed as Wonder Woman fades out of existence — the timestream has shifted so that she never left home or perhaps was never even born. Present-day Batman has a plan: based on his previous examination of the time belt, he has written a program to disable its controls. The problem is catching the villain so he can use it.
Lord Chronos gloats to Enid that he has made something of himself after all. Enid, clearly afraid of him, humors him while trying to talk him into releasing her mother, a suggestion he dismisses. The Jokerz return from their failed mission, and Chronos angrily rebukes them. Wondering how the future Justice League knew when and where to intercept them, he questions Chucko. He then reveals that he already knows the answer, opening a small time-viewer portal to reveal Chucko taking a payoff from the future Batman. To punish this betrayal, he dumps Chucko into the dinosaur age...specifically, the very end of the dinosaur age, just before the asteroid impact.
Present-day Batman goes out looking for leads, and confronts Ghoul. The rest of the combined Leagues arrive, and Ghoul is easily captured. After some questioning, Ghoul tells the Leaguers that Chronos sleeps in a different place each night and doesn't tell anyone where he'll be, but he can tell them where to find his wife. The heroes take down Enid's guards; as they make their entrance, another timeline shift replaces John Stewart with Hal Jordan. Hal declares himself "up to speed" on the situation, and talks to Enid, who readily tells them that Chronos actually sleeps in the Elkhorn jail where he'd been imprisoned during the events of the previous episode.
The heroes move in, as another timeshift restores John Stewart. Unfortunately, Enid ruins their attempt to surprise Chronos by angrily confronting him, giving him a chance to summon the Jokerz. The battle goes poorly for the heroes, with Static being sucked into a time portal and future Batman killed by a gang of Dee Dee duplicates. Chronos then escapes into the timestream again, pursued by Batman and Green Lantern.
Chronos is now racing toward the beginning of time, intent upon reshaping the universe to his whims. Batman and Green Lantern desperately pursue him, finally catching up to him and uploading the program...
Batman and Green Lantern find themselves back in the Watchtower cafeteria. They remember what happened, though Wonder Woman (apparently because she was erased from the unstable timeline) does not.
The final scene is a reprise of the beginning of the story, with David Clinton unable to bear any more of Enid's scolding. He activates a time portal...sending him a few seconds into the past to hear her yell at him again, over and over...
This episode includes examples of:
- Art Evolution: The Jokerz character models from Batman Beyond: Return of the Joker are slightly tweaked for this episode due to the cybernetic augmentations provided by Chronos. Some like Dee-Dee are mostly intact while others like Chucko are significantly overhauled.
- Bad Boss: Chronos deals with Chucko taking a bribe by taking him back to the Cretaceous Period to die in the same meteor impact that killed the dinosaurs. He motivates the remaining Jokerz by threatening them with the same fate.
- Be Careful What You Wish For: Enid wanted her husband to start growing a spine and use Time Travel for Fun and Profit. Now, he’s taken over Gotham City in the future and become rich and powerful by becoming a supervillain, with all the associated psychotic behavior that comes with the job.
- Beware the Silly Ones: Dee Dee's dividual schtick remains intact, but they're a lot more dangerous and vicious than they were in Batman Beyond: Return of the Joker, bragging about having killed a Green Lantern and successfully killing Terry near the end of the episode.
- Bittersweet Ending: The timeline is saved and everyone who died is safe, but Green Lantern is left wondering about Shayera and his future son.
- Bizarre Alien Biology: Played for laughs; Static jokes about a pregnant Shayera laying a child-sized egg, much to John's horror. Warhawk insists that he's joking.
- Book Dumb: After dealing with Chucko, Chronos asks the other Jokerz if they know what killed the dinosaurs. They all ponder it for a second but none of them know, despite this being basic knowledge that children learn.
- Break the Haughty: Ghoul looks forward to fighting the original Batman and isn't that unnerved by Bats' default interrogation attempt, but he's reduced to a trembling child by whatever Old Bruce did to him.
- The Cameo: Due to the unstable space/time continuum, John Stewart is briefly replaced by Hal Jordan.
- Crossover: The episode takes place in an alternate version of the Batman Beyond setting, with Terry as Batman, Old Bruce, Warhawk from the future Justice League, and an adult Static.
- Cyborg: The Jokerz have all been augmented technologically to make them a match even for the Justice League, though the Dee Dee twins don’t have any mechanical body parts.
- The Day the Dinosaurs Died: Chronos punishes Chucko, a lackey who betrayed him, by sending him on a one-way trip back to the Cretaceous. Upon arriving, Chucko scares away a Tyrannosaurus and briefly thinks this means he can thrive in this new home—then he looks up and sees an asteroid flying straight towards him. "Oh, phooey."
- Diabolus ex Machina: Out of nowhere, a group of British soldiers in dress appropriate to the American Revolution appear and shoot at Terry in a panic, leaving the future Batman open to be killed by Dee Dee.
- Everyone Has Standards: Enid may be a jerkass of a wife, but she just wanted her Henpecked Husband to assert himself, not turn into an evil overlord and destroy the universe.
- The Fatalist: Batman expresses surprise that he made it to old age.
- Five-Second Foreshadowing: When Chronos expresses certainty that someone betrayed him, Chucko offers to find out who. That was actually Chucko, who was trying to buy himself some time.
- Freeze-Frame Bonus: At the end, there is a quick flash of Chronos' horrified realization of his fate.
- From Nobody to Nightmare: The former nerdy henpecked husband has become the tyrannical ruler of Gotham City, and is abusing his time-travel powers so badly that the space-time continuum is starting to fall apart.
- Future Badass: Green Lantern is impressed to see that Static went from an inexperienced teen too young to even drive to an accomplished Leaguer with full command of his powers.
- A God Am I: Chronos tries to flee to the beginning of time and shape the entire universe to fit his whims.
- Good Cop/Bad Cop: Old Bruce takes over the interrogation from present-day Batman, getting Ghoul to reveal information about the strength and organization of the Jokerz (and that Ghoul wet the bed until he was fourteen). Present-day Batman suggests that Ghoul had better give them something more useful because "I can't control my friend here much longer".Static: Wow. Batman playing good cop.
Green Lantern: Everything's relative. - Grew a Spine: In the last episode, David was a submissive Henpecked Husband who was easily dominated by his wife and Tobias Manning. Now, after finally having enough of being pushed around, he’s conquered Gotham City, and the Jokerz and his wife are terrified of him.
- Hero Killer:
- Many Leaguers were killed when the Watchtower fell to Earth in the Bad Future.
- Terry gets shot by timewarped soldiers and then is electrocuted by Dee Dee.
- In Their Own Image: Chronos attempts this after his actions cause all of history to unravel.
- Internal Reveal: Bruce learns that he lives to old age and that he'll have a successor (though, given the unstable timeline, he may conclude that this is a possible future but not necessarily the future).
- Matrix Raining Code: Briefly seen on Old! Bruce's computer as he discusses the damage to the spacetime continuum.
- Me's a Crowd: The Dee Dee twins can create additional duplicates of themselves.
- Mike Nelson, Destroyer of Worlds: Chronos' repeated meddling with time throws the timeline into disarray. By the time Batman and Green Lantern show him the chaos that resulted, Chronos believes that the only way to fix it is to reset everything.
- Mythology Gag:
- The beginning of time involves a colossal hand holding a spiral of light. This refers to the Hand of Creation, which has been how the comics depict the creation of the universe (first seen in Green Lantern Vol. 2 #40).
- The white void near the end resembles the anti-matter wave.
- Never Shall The Selves Meet: Averted. Batman and Old Bruce meet and it causes no harm. When Static assumes that this means Old Bruce has already experienced the events as this Batman, Old Bruce states that this is incorrect as he doesn't remember any of this, which explains why no paradox occurs and thus why this trope doesn't happen.Batman Beyond: Batman, Bruce Wayne. Bruce Wayne, Batman. Or have you met?
- Noodle Implements: We never find out what, exactly, Chronos did to her, but Enid tries to ask him to take her mother out of "the thing". Whatever it is, Enid is terrified of it.
- Noodle Incident: Just what exactly did Old Bruce do to scare Ghoul so bad in his interrogation that he spilled his guts? It was apparently worse than being threatened with getting dropped off of a skyscraper.
- Nothing Is Scarier: We don't see what old Bruce does to Ghoul to interrogate him. All we know is that it's more terrifying than threatening him with a fall from a skyscraper. In fact, old Bruce calls young Bruce a greenhorn for effectively interrogating with a death threat.
- Oh, Crap!: Chucko has a very understated reaction to realising that he's about to die along with the dinosaurs.Chucko: Oh, phooey.
- Only in It for the Money: The future Leaguers were able to arrive at the ambush because Terry paid off Chucko.
- Papa Wolf: When Warhawk is nearly killed by Woof, John saves him by blasting the splicer with his ring.John: Get away from my kid!
- The Remnant: Chronos’ forces have reduced the Justice League Unlimited to four members, who are forced to operate out of an abandoned high school where the remaining items from the Batcave are stored.
- Reset Button: Disabling Chronos' time-travel belt causes the universe to (mostly) revert to normal, with only Batman and Green Lantern aware that anything happened.
- Reset-Button Suicide Mission:
- Static is unceremoniously consumed by a time rift during the final battle.
- While Part 1 had presented Wonder Woman as one of the central characters in the story alongside Batman and Green Lantern, this episode has her fade from existence while talking mid-sentence, all before the episode reaches the climactic final confrontation.
- Ret-Gone: The timeline instability causes Wonder Woman to vanish and John Stewart to be briefly replaced by Hal Jordan. In Diana's case, both Bruces speculate in-story what must've happened to her. The best case scenario is Diana never left Themyscira back in "Secret Origins". The worst case scenario is she was never born.
- Ripple-Effect-Proof Memory: Batman and Green Lantern, the two heroes who caught up to Chronos and stopped him, remember the events; for the rest of the universe, none of it ever happened or ever will happen. Lantern lampshades the awkwardness of it all.
- Say My Name: Old Bruce is horrified at Terry's death at the hands of Dee Dee.Old Bruce: TERRY! Terry...
- Sound-Only Death: The audience only sees the beginning of Terry's death by electrocution; the scene cuts away to Old Bruce hearing his screams of agony until they suddenly stop.
- The Story That Never Was: Batman and Green Lantern go from witnessing the beginning of time to...sitting in the commissary on an ordinary day, right where it all began. Lantern still has a head wound, however, and the memory of meeting his son.John: That all...really happened?
Batman: Think so... - Super Loser: With all the power and wealth he's amassed, Chronos is still ultimately a scared little man who sleeps in the Elkhorn jail from the previous episode, apparently because he's gotten used to it and feels safe there.Green Lantern: I don't get it. Of all the places in the city he could stay, why here?
Enid: Because a loser with a kingdom is still just a loser! - Swapped Roles: In the last episode, Chronos was a Henpecked Husband who lived in fear of his abusive wife. Now, he’s a cruel supervillain, and his wife acts meek, affectionate, and respectful to him out of fear.
- Time Loop Trap: Chronos' fate. When he uses his device to escape his wife's rants, a program Batman installed just loops him back to that point. Mercifully, neither of them seem to realize what's happened to them.
- Time Traveler's Dinosaur: The villain Chronos nearly destroys the timeline, causing among other things a prehistoric mastodon to appear in the Batman Beyond time period. He also gets annoyed at one of his minions and banishes him to the Cretaceous where he chases off a Tyrannosaurus... seconds before the asteroid that killed the dinosaurs impacts.
- Took a Level in Badass: The Jokerz gave Terry some trouble in Return of the Joker, but they were still no match for him overall. Here, the tech-based upgrades they were given by Chronos make them powerful enough to threaten the Justice League. The Dee Dees in particular boast of killing a Green Lantern (presumably Kai-Ro) and they kill Terry before the end of the episode.
- Troubled Fetal Position: The heroes find Chronos curled up like this, sucking his thumb, indicating the deep insecurity beneath his supervillain persona.
- Wrong Time-Travel Savvy: Static concludes that the heroes' victory is guaranteed because Bruce Wayne lived to old age; Bruce tells him that it isn't that simple — he has no memory of traveling into the future during his days as Batman, which indicates that the timeline is not stable.
- You Have Failed Me: After leaving Chucko to die in the Cretaceous, Chronos tells the remaining Jokerz that they'll suffer similarly if they fail or betray him.
