Five descendants of the people showered with Bio Particles by Bio Robots five centuries in the past have become Biomen. They transform with the Bio Brace and fight using their Super Electronic Brains on their masks. Their Bioswords are equipped with sword and gun modes.
Bioman must rescue two boys who possess an ancient treasure map that leads to Biobase, making them targeted by Gear.
The Space Empire Zangyack forms an alliance with the Black Cross King, the resurrected form of the Gorengers' enemy the Black Cross Führer, in order to invade Earth with other revived Super Sentai enemies. The Gokaigers, along with the Goseigers, who have lost their powers from the Legend War, must team up in order to fight against the new enemy.
