Ikeda Masaki, called Ikeuchi by his friend, is a college student living alone with his little sister, Minami, who is in grade school, after their father suddenly left one day leaving only a note behind. After thinking about dropping out of university to work and support himself and his little sister, Ikeuchi was encouraged by his best friend, Kanda, who currently has a job after dropping out himself, to continue his studies, and if ever the need arises, Kanda would be there. Ikeuchi believes that even if misfortunes come, as long as he has friends and family, they will be happy.
As time goes on, Ikeuchi gets any part-time job he can get to pay the bills. He eventually forgets Minami's birthday, but is saved by Kanda, who not only remembered it, but bought a gift that the little girl really liked. Ikeuchi notices strange behavior on Kanda's part sometimes, however, he pays it no mind.
