Sometime before events we now recall as the Legend War, the world sees a coordinated assault by the Zangyack Empire that pushes the Goseigers and the enigmatic Gosei Knight to the brink. If not for the timely arrival of the Gorengers and J.A.K.Q. team leaders, Akarenger and Big One, the invaders might have overwhelmed them all. These two legendary captains rally every Sentai team they can muster—the 34 in total—so they can fight as one. With the backing of the supporting heroes who clear safe passage, the assembled Sentai groups stage a defiant stand against the invaders. In a climactic moment of unity, Akarenger calls for a collective sacrifice of their powers to wipe out the armada, scattering those powers across the universe in the process. The depowered teams regroup and part ways, but Aka Red, watching from space, seizes the moment to gather those dispersed powers, turning them into Ranger Keys and helping seed the formation of the Gokaigers.
In the present day, the Gokaigers confront the Zangyack Empire’s second invasion, while the Goseigers reclaim their powers. The invaders retreat for now, but a new threat rises when Warz Gill, the Zangyack commander, is visited by the Black Cross King—the dark embodiment of the defeated enemies of the 34 Sentai teams. The Black Cross King proposes a dangerous alliance with Warz, hoping to exact revenge on the Sentai and their allies in exchange for Earth. As Warz agrees, the Gokaigers begin to explore the Sixth Hero Ranger Keys they recently acquired, while the Goseigers unleash their own mecha to press the attack. Captain Marvelous, the bold leader among them, realizes this is a distraction and prevents Alata from taking Gosei Knight's key, buying time for a deeper confrontation to unfold.
The Black Cross King reaches out more aggressively, stealing most of the Ranger Keys and reviving a trio of former foes—Brajira, Yogoshimacritein, and Dagon, who teleport the Sentai teams to different locations. In the midst of this chaos, Navi—the able ally among them—discovers the Gosei Knight Key, signaling a turning point in their mutual quest. Separated across various places, the Gokaigers and Goseigers reluctantly join forces to take down the resurrected monsters, regroup, and make their way back to their original position. There, Navi and a restored Gosei Knight await, and the two teams agree to stand together to stop the Black Cross King, who uses the Ranger Keys to unleash his own minions.
After a grueling clash, the two factions reclaim the Ranger Keys and weaken the Black Cross King. He then grows in size, forcing the Sentai and pirate allies to unite their mecha in a final, desperate effort. Just when all seems bleak, representatives of long-remembered Sentai teams—Denzimen, Goggle-V, Dynamen, Biomen, Turborangers, Dairangers, Boukengers, and Go-ongers—grant them blessings that reconnect the teams to the powers of their predecessors. With fresh resolve, Marvelous and his crew forge the Super Sentai Bazooka, a weapon born from the combined Great Powers. The Gokaigers and Goseigers rally their forces to drive the Black Cross King back, who reveals his true form as the Black Cross Colossus and unleashes devastation on Tokyo. The Sentai mecha assemble to answer the call, but the Colossus initially overwhelms them, and Gosei Knight falls.
Amid the despair, Nozomu Amachi steps forward on the ground, urging Tokyo’s citizens to hold on to hope and cheer for their Sentai champions. The crowd’s support radiates through the city, reviving the mecha of the Gokaigers and Goseigers and summoning the predecessors’ machines as well. The Black Cross Colossus swarms with an army of revived enemies, but the Sentai mecha strike them down once more. With the heroes weakened, the Gorengers’ ancient power—Variblune—returns to the Sentai and Gokaigers, allowing them to strike a final blow. The Black Cross Colossus is slain, and the past powers fade back to their rightful places as the crowd’s gratitude lights the sky.
In the aftermath, the older Sentai mecha vanish from view, and the people of Tokyo thank the two teams for their courage. The Gokaigers and Goseigers return the Ranger Keys to their rightful owners and entrust the Great Power to the Gokaigers themselves, symbolizing a new chapter for their teams. As the heroes sail onward, Gokai Silver watches from a distance, the quiet witness to a saga that has bridged legend and present in a single, enduring moment.
