Scientifically created zombies roam the world in record numbers. Despite this, anti-hero Aya is determined to track down her father�s killer. With sword in hand and wearing nothing but a bikini and a cowboy hat, she sets off to settle the score. Aya is joined on her path to vengeance by the chubby Katsuji and the beautiful gun-toting Reika. Together, they hack, slash and shoot their way through a sea of the undead to reach a final action-packed showdown with a mad scientist and a pre-destined duel with Aya�s own sister.