El esposo de mi hermano

Yaichi (Ryuta Sato) is a single father and he raises his elementary school aged daughter alone. One day, a foreign man named Mike (Baruto Kaito) visits him. Yaichi has an identical twin brother Ryoji, but Ryoji moved to Canada years ago. They have disconnected since that time. Mike introduces himself as the husband of Ryoji. They are a married gay couple. Yaichi is confused and doesn't know how to deal with Mike.