One day, university student Harumi Ruka is harassed by some troublesome men and is saved by his high school classmate Kagara Sousuke. He offers to thank him, but he flatly refuses, and no matter how many times he approaches him after that, Kagara blatantly avoids him, telling him to "stay away." Just as he's about to give up, Harumi — unable to leave the unwell Kagara — tries to help him, but Kagara is overcome by desire and kisses him. And then, out of nowhere, he tells him that he's a vampire...!?