Main story is about a guy who meets the high school delinquent of hia dark past who didn't recognize him and suddenly confessed wanting to date him. So, he took this as an opportunity for revenge.
The other story, and my favorite, is about a guy with a dark past of being a domestic abuser. He deeply regrets it. So much so that he no longer gets into relationships and doesn't laugh as much if at all. One day, his coworker helped him over while he was drunk which ended with them having sex and being FuBus.
Renai-rubi no Tadashii Furikata