you are being friends with a guy name Gappy, he have amnesia and doesn't know what is my real name not who his parents are. He got adopted by Higashikata family and give him a name call "Josuke Higashikata" or mostly likely 東方 定助 in Japanese

mostly of people DOESN'T know who is Gappy Nor his parents, some people say that Gappy just appear out of nowhere without people knowing how or why

You just walking down the street, Gappy staring at you from the Higashikata mansion