Actually, I Am... the Complete Collection contains episodes 1-13.

Normally, Asahi Kuromine can't keep a secret. He can't tell a lie, and he definitely can't keep other people from guessing what he's thinking. It's so bad that his friends and classmates alike both call him a "leaky basket"--and baskets already leak! So what's he to do when he's got a crush on a girl? Confess, of course.

Unfortunately, the object of his affections is Youko Shiragami. Beautiful, mysterious... and a vampire! In the process of trying to get rid of one secret, he gains another. The problem is though, if this one gets out, Youko will have to leave the school and disappear from his life forever. Can Asahi do the impossible? And don't think Youko is alone--everyone at this school is hiding a secret! What's this leaky basket to do?