Park Eun-jin is a loudmouthed thirty-year-old with an abysmal track record in romantic relationships. Freewheeling and adventurous, she is also irresponsible and reckless, pushing away the timid and the cautious, yet always falling for the romantic dreams of the love-conquers-minor-details-like-my-lover's-married-status variety. After a spectacular break-up with a co-worker, Eun-jin shares a cab ride with Kim Hyeon-seok, a nerdish, awkward young man. Against all odds, they begin a courtship and eventually decide to get married. One night, however, Eun-jin finds a suspicious text message sent to her paramour's smartphone. Angered, she enlists the help of her female cop friend So-young and her doofus ex-marine brother Eun-gyul to get to the bottom of what she suspects is Hyeon-seok's two-timing affair. What she finds out, however, is something else altogether.