Rin is a seemingly normal Japanese high school girl, but on her 16th birthday, everything in her life changes when government special forces break into her home. After witnessing her mother s face blown into bits and her father s severed head falling into her birthday cake, Rin s dormant mutant abilities are awakened: her arm transforms into a sharp, knife-encrusted claw, and a moment later, she finds herself standing in a pool of blood, surrounded by dead soldiers!
Fleeing and fighting her way though her hometown, she encounters a group of girls who were also born as mutants, and call themselves the Hiruko. A breed of mutants who have existed long before the so-called Japanese invaded their homeland and began to persecute them, the girls have different special abilities: one can transform her arms into swords, one can grow tentacles from her fingertips, and one can grow a chainsaw out of her body. The team hone their skills under their demented and powerful leader, Kisaragi, for one purpose: to take revenge on the Japanese who have been persecuting their breed for ages, and to take over Japan and transform it into a land for mutants only! The revenge of the mutant girls will soon begin!