Yuri Saimajima lives a quiet life with her husband Kiminori, with no children. One day, their neighbor Akiko Miyashita invites them along on a trip to Europe, sparking envy in Yuri. However, since both she and her husband frequently travel for work and are often away from home, they instead propose taking care of Akiko's son, Takashi, while they're gone. On the day he arrives, Takashi visits their home. Yuri feels her heart racing—especially after discovering that Takashi is still a virgin. Deep down, something inside her begins to stir.