Ugly Duckling to Beautiful Swan

Satake Kou attended the wedding of his sister's unknowingly that he will be reunited there with his cousin, Fumihiro, who used to be a very dumb and fat guy, then transformed into a charismatic prince! Kou became undeniably self-conscious about this while he is not aware of Fumihiro's high regards towards him since they were little. And in their reunion, Fumihiro's admiration has turned into something complex. How would Kou respond to Fumihiro's feelings?