While her husband, Lee Kang-Joon, was building his career abroad, Sa Geum-Ran—overweight but warm-hearted—spent years enduring the cold treatment of her wealthy in-laws. Her world shatters when she discovers Kang-Joon’s affair with glamorous broadcast announcer Gyo Chae-Yeon. Devastated, Geum-Ran confronts him, only to be pushed into a car accident that is quickly ruled a suicide. But miraculously, she survives. Determined to take revenge, Geum-Ran seeks the help of Han Tae-Hee, an enigmatic plastic surgeon with motives of his own. Under his guidance, Geum-Ran transforms into the strikingly beautiful Sara. The two plot to sabotage Kang-Joon and Chae-Yeon’s wedding, scheduled for three weeks later. But as Sara crosses paths with Kang-Joon in a series of staged encounters, long-buried emotions begin to resurface. No longer driven by revenge, she finds herself wanting not to ruin Kang-Joon, but to win him back. The plan is altered, yet as the lines blur, Tae-Hee realizes he may be falling in love with Sara himself.