"Just for a couple of days until the renovations are finished..." Kumiko readily agrees to let Naoto, the eldest son of the Ueda family, who lives next door, stay at her house. The next day, Naoto visits the Niizawas accompanied by Yuko, the Ueda family's daughter-in-law. Kumiko's son Junpei is also unable to hide his joy at the prospect of starting a new life with Naoto... However, Kumiko cannot forget something Yuko said to her - that Naoto is a "virgin." Curious to know if Naoto is really a virgin, Kumiko makes a bold move after taking a bath...