The human world merges with the parallel world of Kikaitopia and the inhabitants of both worlds begin coexisting. But when the evil Tojitend dynasty begins their invasion, Kaito Goshikida obtains the powers of the Super Sentai across history to transform into ZenKaiser and joins forces with the Kikainoid Juran to fight back.
Kaito and Juran made their decision and in transforming they've grounded their opposition to Tojitendo's forces. In the plaza, a figure was captivated by Kaito's enthusiasm as he was approached by none other than Kikainoid Gaon.
The mysterious individual reveals himself as Stacey, who uses Ijirude's Geartozinger and Dark Sentai Gears to unleash fake versions of the Gorengers, Magirangers, and Boukengers against the Zenkaigers.
The Zenkaigers manage to reach a truce with the World Pirates and convince them not to commit any acts of piracy. However, a strangely cheerful Zocks continues to endanger civilians while fighting Tozitend's Mahiru World.
The Zenkaigers and World Pirates find themselves in a strange game of "oni tag", wherein people designated as "oni" can turn others into more oni by touching them.
After defeating Dai Recycle World and receiving an invitation from Stacey, Zocks challenges Kaito to a duel under the promise of having him assist in accessing Tozitend's base to obtain the SD Toziru Gear.
Barashitara employs the help of Kabutomushi World to send the Zenkaigers and World Pirates into a rhinoceros beetle hunting illusion, doing so under the premise of providing Tozitend with a supply of free labor.
After Magine is kidnapped, the other Zenkaigers look for a way to rescue her. Meanwhile, Zocks returns from the World of Saber, but is followed by the Shindai siblings, who want to settle a score with him.
Tozitend deploys Copy World, who is capable of making evil copies, to attack the city. The Zenkaigers and World Pirates attempt to fight back, only to learn evil versions of Kaito and Zocks were produced. In order to face this threat, the real Kaito and Zocks will have to combine the power of their Zenkaiju Gears and form a new mecha.
Stacey uses Battle Caesar Robo II and an army of Sentai copies to overwhelm the Zenkaigers and their mecha, though Kaito has doubts regarding Stacey's conviction.
Tozitend deploys Vacances World to attack the city, and the latter appears to succeed quickly. Seeing no harm in the World's actions nor in taking a vacation, the Zenkaigers and World Pirates join in on the fun with their opponent, but Barashitara was forced to kill Vacances World after his attack affected even the entire Tozitend army while forcing the latter's Toziru Gear into one of the Kudaitests. After the fight, the Zenkaigers were reprimanded by Yatsude for leaving Colorful in mess during their time under Tozitend's influence.
Certain that Mitsuko escaped to another world, Kaito begins searching for her across the worlds he and the Zenkaigers previously liberated along with Juran, Magine, and the World Pirates while Ijirude orders Stacey to look for her as well.
Tozitend sends Manga World to turn people into manga characters. The Zenkaigers fight back, but Juran and Magine get trapped in a manga and learn they have to survive or else they cannot return.
The Zenkaigers find themselves facing off against Reverbating World and Tozitend hitman Hakaizer, who wields a gun capable of summoning multiple past Sentai members at once.
Accepting the revelation that Hakaizer is Isao, Kaito tells Zocks, who agrees to help him save Isao. While working on a plan to lure out Hakaizer, the Zenkaigers and World Pirates have to face Bikkuribako World.
As Tozitend sends a radish-themed World capable of manipulating discarded items to attack the Zenkaigers, Magine and Flint help a little girl who seems to be searching for something.
As the Zenkaigers and World Pirates prepare to celebrate Kaito's birthday and Christmas, they find themselves under attack by Bon World, Shougatsu World, Stacy, Hakaizer, and all of the combatants' ancestors.
The Zenkaigers and World Pirates attempt to continue celebrating Kaito's birthday, Christmas, and New Year's, but Shougatsu World attempts to use his powers to make them forget the past year.
Ijirude upgrades Hakaizer and gives him a mecha called HakaijuOh to overwhelm the Zenkaigers. In response, Kaito resolves to face Hakaizer with everything he has and get his father back.
With Isao free of Tozitend's brainwashing, he and Kaito are able to reunite after being separated for so long. However, their reunion is short-lived when they, the Kikainoids, and the World Pirates become embroiled in a culinary competition to determine whether soba noodles or udon noodles are better.
Tozitend sends Kotatsu World to weaken the Zenkaigers and World Pirates' resolve with his namesake, leaving the heat-sensitive Juran to face the new World and Barishitara alone. In desperation, he uses a strange Sentai Gear unconnected to his Sentai predecessors to summon a new hero.
Tozitend sends a weathercock-themed World to use its wind-based powers to overwhelm the Zenkaigers and World Pirates. Stacy seemingly defects from Tozitend to aid the heroes, but they are suspicious of his uncharacteristic smiling and sudden change in sides.
With SDtopia and Kaizokutopia freed from Tozitend's clutches, the World Pirates leave to pursue a new journey. However, the Zenkaigers are attacked by Omikuji World, who is capable of manipulating their fortunes
With Stacy free from Gege's control, the Zenkaigers join forces with him and the returning World Pirates to mount an assault on the Tozitend Palace and defeat them once and for all.
Tozitend was destroyed, Kaito reunites with his parents, and both the World Pirates and Stacy leave to move with their own lives, but Earth and Kikaitopia was separated and Kaito lost his memories of his time with the other Zenkaigers.