Hikari, who has been supporting herself with her younger sister. She decides to leave home because her younger sister has found someone important, but she is persuaded to stay and is now living happily with her sister's family. One day, after a series of overtime shifts, she dozed off on the train, lulled by the swaying motion. When she woke up to the sound of rough breathing, her sister's husband was there, looking up her skirt and stroking his dick...
