In the Time Nest, headquarters of the Time Patrol, the Supreme Kai of Time informs Xeno Trunks and Xeno Pan that her mystical bird Toki-Toki has disappeared. She sends the two of them to find him, while also being worried about a supposed "Bird of Catastrophe" that has been released. Meanwhile, Toki-Toki has appeared on Earth in the main timeline, where Goku finds him while training with Vegeta, Gohan, Piccolo, Krillin, and Android 17. Xeno Trunks and Xeno Pan arrive and are happy to see that Toki-Toki is safe, with Xeno Pan explaining that his existence is very important for the inner workings of the multiverse. Suddenly, the group is interrupted by the arrival of all twelve Gods of Destruction.

Fu, accompanied by an unknown female companion, meets with a group of villains - Meta Cooler, Turles, Bojack, Super Android 17, and a mysterious humanoid scientist known as Dr. W - on the Universe Tree, where he reveals that he rescued all the villains from the moments before their deaths at the hands of the Z-Fighters and convinces them to help him in exchange for places in the new universe that he is creating. Meanwhile, Goku, Vegeta, Xeno Trunks and Xeno Pan are searching for Fu, when they are attacked by Turles and Bojack. The two villains reveal that Fu has been able to increase their power immensely, as they are now strong enough to fight on par with Goku and Vegeta's Super Saiyan Blue forms and have auras similar to Cumber's. As the battle rages, Xeno Trunks spots Fu observing the fight: Goku and Vegeta try to engage him instead, but Turles and Bojack block their way. Elsewhere, Xeno Goku and Xeno Vegeta arrive in Hell, and are confronted by the mysterious Dr. W.

Dr. W begins what he calls an "analysis" of Xeno Goku and Xeno Vegeta by attacking them with strange, teleporting energy blasts. They both power up to Super Saiyan 3 and engage him in combat, but he is able to hold them both off with his strange attacks and high-speed reflexes. After having difficulty overpowering him, they power up to Super Saiyan 4 and land a powerful combined blast on him; however, Dr. W deliberately takes their attacks head-on, and emerges from the smoke with a glowing golden aura identical to theirs. Having completed his analysis, he then opens a portal and escapes. Meanwhile, Fu is observing the battle between Goku, Vegeta, Turles and Bojack. He releases Doki-Doki, who generates waves of dark energy that immobilize Goku, Vegeta, Xeno Trunks and Xeno Pan. Toki-Toki tries to defuse the dark energy, but Fu traps him and throws him through a portal, before recalling Doki-Doki and escaping through one himself.

In Hell, Xeno Goku & Xeno Vegeta, even both as super saiyan 4, struggle against the reborn Janemba, who is aware of all of their abilities and tactics, which enable him to easily overwhelm both saiyans. Just when Janemba is about to finish them off, Xeno Trunks, Xeno Pan, Goku & Vegeta arrive in Hell through a wormhole, joining in on the fight. Xeno Trunks powers up to Super Saiyan 3, while Goku & Vegeta both power up to Super Saiyan Blue. Super Saiyan Blue Goku And Super Saiyan 4 Xeno Goku then team up and begin to overpower Janemba with their simultaneous attacks. But not long after, Putine & Majin Salsa arrive in Hell and knock back Janemba, enraging Dr. W by interfering in the fight.

Xeno Trunks identifies the new arrivals, Majin Salsa and Putine, as demons and old enemies of the Time Patrol. However, the demons offer to help the heroes in their efforts to destroy Fu's Universe Tree, warning that the Tree is continuing its work of consuming countless planets across the multiverse. Janemba attacks them all again before the two groups can come to an agreement, and the battle resumes, with Xeno Trunks powering up to Super Saiyan God. Majin Salsa suggests that Xeno Goku and Xeno Vegeta use a mysterious technique that they have employed in the past, so the other Saiyans all power up and channel their energy into the pair while the two demons hold off Janemba. By absorbing the others' energy, Xeno Goku and Xeno Vegeta break through their limits and achieve a higher level of strength, known as Full-Power Super Saiyan 4. They attack Janemba together, succeed in overpowering him, and are finally able to destroy him using their ultimate technique, the Double Dragon Fist.

Towa restrained Xeno Goku, Xeno Vegeta, Xeno Trunks, and Xeno Pan in her artificial space using Cumber's dark ki, and proceeds to reveal Fu's nature as her creation using data from previous Dragon Ball fighters and villains. She explains that her plan is to make Fu as the new Demon King using Mechikabura's ki she stored in a dark energy orb upon his death. Xeno Goku manages to break free and attacks Towa, only to be blocked by Mira. Towa teleports Xeno Gohan and Xeno Goten into the space, both unconscious as their ki has been drained before, then teleports Mira and herself out as the space breaks, pulling all inside into something like a black hole. Meanwhile, Vegito in Super Saiyan Blue is fighting Fu in the front of Universe Tree and seemingly getting the upper hand.