When Kamen Rider Build Meets Martians

Who says the Martians are all extinct? Hope, the last Martian, is entrusted to Pandora's Box as the hope of saving the universe.

A new Kamen Rider, Kamen Rider Firain, makes his debut, transforming with the Squeeze Driver and Phoenix Jelly. Is he friend or foe?

Will Soichi Isurugi, whose plans have been thrown into disarray time and again, really let this go?