While his wife is away visiting her family, Tatsuya’s sister-in-law Akari unexpectedly stops by to check on him. Lonely from doing the housework by himself, he gladly welcomes the company, but Akari keeps pressing close and leaves him flustered. A single look from the beautiful woman is enough to make him painfully hard. He retreats to the bath to calm down, only for Akari to come wash his back and climb into the tub with him, beginning two days and one night of nonstop release.