"When was the last time you had sex with your husband...?" Chihiro confided in her friend Mie. Sensing Chihiro's inner turmoil, Mie suggested a trip together—just the four of them, including their husbands. A few days later, they headed to a barbecue site under perfect weather. While Mie's husband Ryuichi was away out of sight, Chihiro secretly let Mie touch her body, stealing moments behind their spouses' backs. It was an illicit affair—wrong place, wrong person. Chihiro felt strange sensations coursing through her body, as if forgetting who she really was. Then, days later, Chihiro's mobile phone rang...