Nana married her former boss a year ago and now lives peacefully with his adult college-student son, Kazuki. Her husband cooperates with their efforts to conceive, but his low libido and dutiful, passionless sex leave her frustrated and unsatisfied. Then he is sent away on a long business trip. As soon as Nana and Kazuki begin living alone together, he starts touching her more often under the excuse that they are family. Nana is confused, but with her husband gone, every touch awakens a quiet sexual ache in her neglected body.