Three men and women start living together. Byeong-soo is chosen in a scenario contest and is picked to write a script for a movie, so he leaves the noisy city and moves in with his married senior from school. At the house is Ji-eun, the senior's wife and a young and sexy Bo-yeong.  The three living together leads to some risky situations!

Young Sister-In-Law

A sexy sister-in-law instead of a quiet wife!  An innocent sister-in-law instead of a horny wife!  Two men struggle with their sex lives and they decide to swap wives.  Jong-woo is frustrated with his wife Jae-hee because she's so silent in bed. He talks to Ji-yeong about this and she tells him she hasn't had satisfying sex ever with her quiet husband Min-soo. Jong-woo and Ji-yeong find out they enjoy various positions and plays and end up spending a night together. Meanwhile, Jae-hee and Min-soo also want something soft and affectionate and the couples can't be stopped now...