Chuuya is comfortable with his life until a new encounter puts him on edge.

"Dear, past me I know you're a bit confused but please believe me on what I'm about to tell you. Chuuya, I'm you from the future. I'm writing this before my death. Yep, you're going to get assassinated in the next six months. By a man in which you do not know of. This man is named Dazai Osamu, he will then after kill himself for being tired of the world. I need you to stop your own assassination and his suicide. How, you ask? By making him fall in love with you and helping him escape the mafia"

The ADA made a list on what Dazai can not do.

This is a list piled up by the mafia on what Chuuya should not do.