After moving into an apartment in Tokyo, Ozawa one day overhears his neighbor, Iroha, talking on the phone with someone he assumes is her lover. Later, seeing her off as she waves goodbye to her husband, he realizes she is a married woman—and becomes increasingly curious about the man from the phone call. Soon after, he spots Iroha walking closely with a young man, further fueling his obsession. Driven by curiosity, Ozawa secretly films their rendezvous and uses the footage to blackmail her, forcing her into a twisted relationship. A scandalous affair unfolds in the quiet apartment complex, blurring the lines between desire, guilt, and betrayal.