Seong-yeon is dissatisfied that her sex life is not smooth due to her husband Sang-woo's frequent overtime work. But she found a different kind of pleasure: covert sex with her brother Sihuo. Her Si-hoo forces her girlfriend Joa to come into her house to stay away from her Jeongyeon. As soon as her open and shy Joa arrives at her house, she unexpectedly takes a nap and wakes up to arouse Sang-woo.