A middle-aged gangster finds himself body-swapped into the body of a bullied teen. Now inhabited by a tough-as-nails gangster, the teen starts to fight back against the power structure at his school and change his miserable existence.

A poor, widowed woman, desperate to support her 7-year-old daughter, and a wealthy business executive with a sick mother enter into a contract marriage together.

Whenever elementary school teacher Kang Joon-soo (Lee Seung-gi) falls in love, he always gives too much of himself to the relationship. Yet despite that, he ends up being the one getting dumped by his girlfriends. Joon-soo has been friends for 18 years with Kim Hyun-woo (Moon Chae-won), a weather forecaster whose beauty belies her witty tongue and aggressive manner.