This is a romantic mystery drama that will depict a murder and a romance story taking place in a luxury hotel. Nam Sang Hyo is the manager for the wedding department of a hotel. She is a perfectionist with a bright personality. She meets her ex-husband Koo Hae Young as a client at the hotel. Sang Hyo and Hae Young were in love and married 7 years ago, but they divorced less than 100 days later. A murder case in the hotel gets in the way of the wedding and throws the characters into unexpected situations. Meanwhile, Jo Sung Gyum is the management director of the hotel and Sang Hyo’s boss. The murder case that brings about a crisis at the hotel is related with his personal history. He is in a love triangle with Sang Hyo and Eun Joo. Eun Joo works as public relations manager for the hotel. She is ambitious with her work career .

In 1993, Jisu and Jaehyeon, who met for the first time at the protest scene and being a first love to each other. After 26 years, Jisu and Jaehyeon accidently reunite.

When Nini gets her hands on what she thinks is a pebble, she decides to keep it and forgets about it. Little did she know it was actually a priceless rough diamond that belongs to a big mafia boss. When she starts being chased by those who are after the diamond, the only person who can protect her is Nakan, the man who broke her heart three years ago.

Nakan's case requires a believable decoy, so he and Nini must team up. Their relationship is supposed to end when the case is closed, but Nini has a few tricks to pull.