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.

Set in the Joseon Period, three beautiful musketeers fight against a powerful group who tries to overturn the royal family and gain absolute power. The leader of the Beautiful Three Musketeers is Jin-Ok (Ha Ji-Won), a smart and righteous woman. Hong-Dan (Gang Ye-Won) is the only married woman among the three women. Ga-Bi (Son Ga-In) is the youngest among the musketeers and excels at fighting.