Nakayama Aya is a 32-year-old housewife who has been happily married for two years. To others, Aya and her husband seem like a perfect couple. Aya notices a message from a mysterious woman on her husband's cellphone, leaving her to wonder if he might be having an affair. She then remembers that they have not been intimate in the past two months. Aya begins her search in earnest for additional evidence of a potential affair.