A Regular Epic Final Battle

Prior to the events of the episode, Pops is upset about the upcoming fight and is put in a very bad mood. The gang at the park cheer him up by throwing him a party. In order to remember the events, all of their memories are put onto a collection of Blu-rays and buried in the park. They set a course to the location of the fight, Lolliland, Pops' home planet.

An epic final battle begins and concludes, all deciding the fate of the universe. The park crew arrives at Lolliland, the place of birth of Pops and Anti-Pops. The place is shattered of all the old fights the two brothers had and there they meet a group of natives from Lolliland, Frivola-Kranus, Quadravi-Kranus and Weird Mushroom Guy, they tell the crew of the previous battles Pops and Anti-Pops had, also they discover Pops' real name, Mega-Kranus and Anti-Pops', Malum-Kranus, and how the Lolliland natives have been evolving to the point Pops was born.

In the ancient tapestries show every battle ever done, and there is a section where warriors resembling the park crew are fighting along Pops, meaning they were meant to fight in the ultimate battle, but now that they know that they are meant to end the fight in a stalemate. Mordecai comes up with the plan of setting traps for Anti-Pops so they get an advantage in the battle. Pops is against the idea at first, but he was also convinced that they have to win to save themselves so he helped them to set the traps.

Anti-Pops arrives in a Uber-like taxi, Pops still tries to convince him not to fight, but Anti-Pops refused, after singing the Lolliland anthem, Anti-Pops started the fight but everyone had struck him with the traps, at first they were excited about defeating Anti-Pops but then he returned, unscathed from the traps.

Pops still wants a fair fight, so they make a deal of who ever knocks the other first, can do what they want to the universe, they both agree and start to fight, which in the first round Pops crushed Anti-Pops with a cruise boat, but Anti-Pops breaks the deal and continues the fight while the park crew fought against Anti-Pops' minions, as well as Streaming Modem who wants to destroy the disc masters, but they are aided by HD DVD and Blu-ray, the Baby Ducks, Toothpick Sally, Recap Robot, the real Chance Sureshot (it was a clone of the one that died), the Guardians of Eternal Youth, Gary, Carter and Briggs, Death, Party Horse 42699, and the Guardian of Lolliland (even she isn't supposed to participate), the Baby Ducks form another mecha with Skips, Eileen, Benson (on top of the hat), the Guardians of Eternal Youth, Gary, Carter and Briggs, Death, and Party Horse 42699, then they fight the modem, Anti-Pops minions' shoot down Rigby's ship but are caught by Mordecai, and Chance shoots the Uber driver, the modem is beaten with Gary's synthesizer, a shock wave from Blu-ray and HD DVD, and an elbow drop from the guardian of Lolliland.

As they end the first part of the battle, Anti-Pops reaches his ultimate power and starts erasing Lolliland, Muscle Man and HFG are caught in the erasing beam and Pops tries to save them but he is too scared of failing, so Muscle Man said his last "my mom" joke before dying. With their death, Pops gets angry enough to reach his ultimate power and the real cosmic battle starts, both brothers fired their beams on Lolliland, but Pops is still scared of failing and Anti-Pops who is currently stronger erases everyone, including Andy, the long-lost teenage brother of the Baby Ducks, except Mordecai and Rigby.

With the death of almost all his friends, Pops engages the fist crash that would reset the universe, Anti-Pops would counter-attack it, as Mordecai and Rigby were looking at it, Mordecai thought of shooting Anti-Pops before their fists collide, but their shots didn't affect him and they are caught in the middle of the punch, obliterating the entire universe and resetting time.

After the events of the end of part two, we see the first part of the first episode "The Power". It stops at the point where Rigby is about to crash into the wall, and he recalls the events happening. Rigby tries to convince Mordecai, but he doesn't remember. Rigby then goes to where they previously buried the Blu-rays which contains all their memories, Mordecai touches it and remembers everything. Realizing that time didn't properly reset, they use the Power to take them to the fight in the future. Pops and Anti-Pops are still fighting and Mordecai and Rigby appear, which leaves Pops surprised. Anti-Pops blasts them, destroying the Power in the process. When it becomes a stalemate again, Pops realizes what he must do to stop the reboot of time. He does this by sacrificing himself and Anti-Pops into the sun. After this, time continues and we see the future lives of the park gang as they return to Earth after being in space for three years in earth time.

Mr. Maellard becomes depressed and mourns for his son, so the park workers erect a memorial for Pops, Mordecai and Rigby quit their jobs at the park and move on with their lives. Mordecai finally makes his dream of being a painter come true and meets a woman named Stef, a female bat he genuinely loves and has three children (two sons and a daughter) with her (and though he never reconnects with either Margaret or CJ, he does consider them his muses and incorporates their appearances in his art). Rigby settles down with Eileen, with whom he has two daughters. Muscle Man reunites with his wife, Starla who is revealed to have been pregnant with his daughter when he left, and the three of them move to a nicer trailer and continue to have children.

High-Five Ghost and his girlfriend, Celia, become party DJs touring in Prague and later have a son. Benson, who now becomes the owner of the park after Mr. Maellard passes on, reunites with Pam and the two adopt four cats along with Applesauce, Benson's pig. Skips is still single and still working in the park, only now he is wearing jean shorts (or jorts) instead of jeans. At their 25th anniversary reunion, Skips and Muscle Man raise the statue of Mr. Maellard along with the previous Pops. A now middle aged Mordecai and Rigby remember the sacrifice of Pops and laugh at how immature they used to be before deciding to play some old arcade games. This episode ends with the revelation that Pops is watching his friends from Heaven on a VHS tape labeled "Regular Show". He ejects the tape and says "Jolly good show" as the series officially ends set to the 1977 David Bowie song Heroes.