C-2678 - My wife's friend, a 30-year-old married woman, stayed over and things got out of hand

A married woman who ends up spending the night with her friend's husband crosses the line. Two months later, they reunite in the city and head to a hot spring. 1st: The affair begins as they forget their lonely lives. 2nd: They meet again and give in to pleasure. 3rd: They indulge in their desires at a hot spring inn.