Nishino Kanako used to be an ordinary office worker, but somehow she wound up with a dangerous new gig: working as a hitman! Her unexpected genius as the notorious contract killer known only as "K" has amassed a fearsome reputation in the underworld. Unfortunately for Kanako, that reputation has drawn the attention of a rival hitman, who's made it his goal to take her life. Meanwhile, she finds herself in uncharted territory after her mysterious and handsome next-door neighbor takes an interest in her! Those two things couldn't possibly be related, right? Nah, no way...