Hotaru's husband died in a traffic accident, leaving her to care for her father-in-law who suffers from dementia. The accident's aftermath brings immense guilt as she's blamed for her husband's death, plunging her into emotional turmoil. Under this psychological strain, her father-in-law's condition worsens, and he begins expressing increasingly aggressive sexual desires toward her. Unable to escape her circumstances, Hotaru ultimately surrenders to his advances. This intense, dramatic narrative weaves a story of grief, obligation, and forbidden desire.