Wakaba, a schoolgirl, struggles to remember her first love for inexplicable reasons. Despite donning a pendant, the piece's source eludes her, and she assumes it to be a present from her lover. The intricate key merely conjures up images of a tearful boy and the scents of roses and blood - insufficient clues to recollect her past relationship. However, fate works in mysterious ways.
Wakaba stumbles upon a rose garden, where a weeping boy catches her eye. As she tries to leave, she pricks herself on a thorn, and the boy licks her wound. Though an unconventional first-aid remedy, her pain subsides as she catches a glimpse of an extremely familiar pendant around his neck.
Upon learning that the boy, Yukito Haibara, is a new transfer student, Wakaba ponders if he might be the one who stole her heart. However, her memory loss's root cause, Yukito's reluctance to be intimate, and gossip about vampires in her chemistry class leave her with doubts.
The book's additional one-shots are "Bloody Honey" and "Un Chocoholic."
