In a post-apocalyptic wasteland, elite Oasis rules the oppressed Undercity with advanced mechs. The Undercity chief holds a tournament for his daughter’s champion and suitor, but arrogant Oasis nobles storm in to enslave her. Mech prodigy Kaelion, who pretended to be a useless playboy to evade his vicious stepmother, drops his disguise. He summons a mighty mech, crushes the nobles, igniting a rebellion to restore the Undercity and avenge his mother.
