A romance drama about two female high school students who happen to share the same name. When they both transfer to a new school at the same time, hoping to use the opportunity to turn their lives around, they forge a secret contract to swap identities. Shin Yi Joon is the most popular student at his high school. Although he seems tough and aloof on the outside, Shin Yi Joon is actually a huge softie on the inside—and far from getting into fights with other students, he even has a hard time saying no to other people.

Ki Moo-Hyeok, a lawyer with a high winning rate, only cares about money. Due to a murder case at a high school which he deals with, his reputation as a lawyer hits rock bottom. To regain his good name as a lawyer, he sneaks into the high school and work as a temporary teacher. He tries to reveal a secret which the students have, and gets involved with Teacher Ha So-Hyun, a P.E. teacher who loves her students. They then face the students'secret.