Hiroki's sister was killed by a friend. Hiroki then meets the killer's sister, Futaba, 15 years after the incident. Both of their families have been burdened with grief, but through their meeting they struggle to find a brighter tomorrow.

Fukami Hiroki's younger sister was killed by a friend. Hiroki then meets the killer's sister, Toyama Futaba, 15 years after the incident. Both of their families have been burdened with grief, but through their meeting they struggle to find a brighter tomorrow.