Mizuki is a simple teenage boy. Adopted at a very young age, he knows nothing of his past and his real birth parents. Life is troublesome for him, as he is chained down by an unusual condition: he throws up every morning once he wakes up. Mizuki's life starts to change around him the moment he meets a new boy who has just moved to his town. Soon, this boy takes in interest in Mizuki, and his curiosity gets the best of him. Who is this unusual boy? Will Mizuki learn of his past? And most importantly, what are his adoptive parents hiding from him?