On the outset, the Okunos seem like a normal happy family with father Tadashi and his two bright sons, genetics researcher Izumi and artsy Haru. When a series of arson attacks strike the neighborhood, clues left at the crime scenes seem to be somehow related to the Okunos. Izumi and Haru try to get to the bottom of mystery, slowly unveiling a tragic family secret that has come back to haunt them.