SONE-669 In the afternoon, when the wife in the neighboring apartment hangs her panties on the balcony, it's a sign that her husband is not home. Reika Kuroshima

(Today, there are panties hanging on the balcony again. That's our signal to have sex.) Rei, newly married, feels suffocated in her conservative husband's relationship while harboring sexual frustration. One day, a middle-aged bachelor, Nakata, moves in next door. From their encounter, Rei's desires gradually begin to unravel. Rei secretly hangs underwear on the balcony as a sign, and the two start a secret relationship. She invites him into the room under the pretext of repairing the air conditioner, and they have trysts while her husband is away, with Rei becoming increasingly bold.