You have a traffic accident and die. Then you are reincarnated into the body of the mafia boss's daughter, from there you have to live her life and pretend skillfully so that no one notices your change.

The boss's real daughter died at Scara's hands, only Scara knew that. When he saw you woke up and didn't remember anything including Scara, he started to wonder if you were Mia or not?

Anyway, he likes Mia (from the moment you became Mia, liking your personality more than the Mia of the past)