Mary, working a side-job as a driver for her gold-digging girlfriends in crowded Hongdae, gets into a car accident with a random guy. The victim is the indie band vocalist Kang Mu Gyul. Mu Gyul, late for his concert, leaves saying he's fine. Mary runs after him to get an affidavit confirming he is uninjured. She happens to see him perform with his band. The affidavit blows away in the wind. Mu Gyul gets drunk and causes an accident that can't be reversed.

Dae Han, mistaking Mary and Mu Gyul to be dating, goes to the hotel and presses Jung Suk to expedite Mary and Jung In's marriage. Unbeknownst to the people involved, the two fathers urge that they meet. Mary, waiting in the lobby for her father, runs into Hallyu star Lee Ahn and Manager Bang. While getting an autograph that she wants to show off to her friends, Mary goes through a crisis when Manager Bang attacks her. A volatile situation! A knight riding a white horse appears before Mary.

Mary begins working for JI Entertainment! However, Jung In, the polite jerk, doesn't give Mary any work, and she suddenly becomes an indebted lady of the manor. Meanwhile, Dae Han is suspicious of Mary and Mu Gyul's relationship. Mary attempts to reassure her dad with ridiculous words, but Dae Han is not easily fooled by such lies. Mary has no choice but to head toward Mu Gyul's house. Events begin to unfold that lead her to a double life between Mu Gyul and Jung In.

Jung In is filled with concern after he receives notice from the broadcasting company that a time slot has not been approved. When Jung In shows a lukewarm attitude toward his marriage with Mary, a dissatisfied Jung Suk gives him an ultimatum. If, even after 100 days, if he is unable to win Mary's heart and marry her, he will withdraw his investment.

Mary and Jung In spend a day at the vacation house sharing a childhood memory. Jung In shares that he will do his best from now on to win Mary's heart, and Mary feels warmth and emotions from him for the first time. That night, Jung In faces a painful and terrifying memory of his father, Jung Suk, in a nightmare.

Mu Gyul finds out that Manager Bang's contract, which Mary asked Jung In to review, is invalid. Mu Gyul goes directly to Jung In and angrily tells him not to get involved in his affairs before turning away. Just then, Mu Gyul hears Jung In's guitar playing, and much different from what he had assumed, discovers Jung In's passion for music and authenticity.