Follows a former female boxing champion that now works as a substitute high school teacher and how after witnessing intolerable violence, she decides to take justice on her own fists.

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.