Baek-seon and Soo-kyeom are a sex-less couple who have been living with each other for 20 years out of loyalty. The two decide to find a hobby for some fun in their lives. Soo-kyeom decides to get personal training and Baek-seon decides to get some art tutoring. They meet handsome and young personal trainer In-hak and pretty art teacher Ji-won! The couple is soon more interested in getting action than getting lessons. What will be the end of their secretive lessons? Who's going to let down their guard first?