Nam Sang-hyo is the head of the wedding planning division of The Secret Hotel, one of Korea’s most elite and luxurious hotels and considered among the top wedding destinations in the country. Optimistic, cheerful and a perfectionist, she works hard and dreams of becoming the hotel’s general manager someday. Sang-hyo faces the biggest challenge of her job when her next client turns out to be architect Gu Hae-young, her ex-husband. Seven years ago, Sang-hyo and Hae-young fell madly in love and got hitched in Las Vegas, but because of Hae-young’s easy-come-easy-go attitude towards relationships, they fought and broke up. Since the marriage lasted only 100 days, they never filed the paperwork to legally register it, so their short-lived marriage remains a secret.
Meanwhile, Sang-hyo has caught the eye of her boss Jo Sung-gyeom, a strict but thoughtful hotel managing director who has all the female employees swooning. But there’s also ambitious public relations manager Yeo Eun-joo, who competes with Sang-hyo for both a promotion and Sung-gyeom’s heart.
To make matters even more complicated, a murder turns the hotel topsy-turvy. Sung-gyeom may be connected to the case, while Eun-joo attempts to use the circumstances surrounding the murder to get a leg up on the corporate ladder. As Sang-hyo and Hae-young juggle their sudden reunion under awkward circumstances, the exes also get sucked into the murder investigation