Tsuki no Hana

Filled with guilt and confusion over his student's bullying and suicide, a teacher loses himself as the toy of a sadomasochistic pair of lovers. One of them is an ex-classmate of his who used to get bullied by the rest of the class. Through playing their twisted games, he hopes to find some sort of answer. But will he get it? Is there really one? Also contains two side stories and a followup to the main story.