Reiko Makihara, a married woman who lost her husband—a high school teacher—recalls a secret she had kept from him during the wake, shedding tears of sorrow. It was a single, regrettable affair she had with Aso, one of her husband's former students. That night, as Aso gently comforts her while they remain behind after the wake, Reiko, seeking escape from her grief, ends up sleeping with him once again. Later, she overhears another student say, "The teacher was troubled because he found out his wife was cheating." Realizing she now bears an unforgivable sin, Reiko, a grieving widow, is drawn deeper into a future filled with endless suffering and inner turmoil…!?