Orphaned at a young age, Hiro Hiyorimis young life is cut short when he is killed in a freak accident. Luckily for him his sister recently accepted a job as caretaker for Hime a member of the royal family who has inherited the Monster Kingdom and rules over her dynasty with a chainsaw! Granted a second chance at life, Hiro is eternally grateful (if somewhat confused). Immortality has a price: regular infusions of Himes blood and servitude to the Monster Princess.