Mizuki lives happily with her husband. But her life takes a turn when she meets Kensuke, a younger man, and begins a secret affair with him. Though content in her current life, Mizuki finds herself drawn to Kensuke's honest and affectionate nature, craving the excitement he brings. One day, Kensuke breaks their agreement by showing up at her home, and Mizuki, panicked, turns him away. She cuts off all contact—until she suddenly receives a message saying "I want to see you." Leaving behind a false note, she heads to meet Kensuke once again.