Hiro Hiyorimi is a boy who has just moved to the Sasanaki City to meet his sister. While walking down the sidewalk, he is suddenly hit by a car (crushed by construction beams in the anime). On the verge of death, he is seen by a young woman. She then resurrects him, leaving him alive in the hospital (morgue). He wakes up confused over what happened, only to encounter the woman again as she eliminates some wolf creatures. She addresses Hiro as “her servant” and introduces herself as “Hime” (Japanese for Princess) and explains that she is a member of the royal family of the Monster Realm.
All members of the royal family are endowed with the power to turn a dead body into an immortal warrior that will serve and protect them;
Hiro is now Hime’s semi-immortal warrior, but she herself is not immortal yet (which is why she needs help from warriors). The story then follows Hiro as he assists Hime in killing creatures that have been sent by her siblings to attack her in the competition for the Monster Kingdom’s throne.
Hime has another servant named Flandre. Later on in the story they encounter Hime’s younger sister Sherwood, Sherwood has an android named Francisca. They also encounter a vampire named Reiri and a werewolf named Riza.