In-seon is about to leave to Spain as a foreign exchange student when she hears shocking news from her terminally-ill mother. Her father she thought dead, was alive and she was born when he raped her mother. While she had inner conflicts about her existence, she decides to find him and kill him. She disguises herself as his previous wife's relative and starts living with him and In-seon's actions of revenge gradually collapses...

Dong-hyun is a high school student. One day, he falls from the rooftop and bumps into Pan-soo who is a passerby. Pan-soo is a member of a criminal organization. When the two men wake up in the hospital, they discover that they have switched bodies.