Eun Yi works as an editor for a fashion magazine. She is a very strong and confident woman and she appears cold. She doesn't get along with her colleagues and she was dumped by her last boyfriend. She's very cold, tough, and seems to have no expression at all. In Ho was a ballet dancer. However, he lifted a female dancer once, but dropped her by accident. Due to the accident, that dancer could no longer dance. Therefore, he refused to dance with women from then on. In Ho now has hopes of being a musical choreographer but he has no place to stay. His friend, who happens to be Eun Yi's little brother, decides to bring him over to his sister's house.
He makes a deal with her saying that if he lets In Ho stay for one night, then he'll take care of their parents' situation so that they would never speak of divorce again. She agrees, thinking it was only for one night. However, her brother makes a different deal with In Ho. He makes In Ho pay rent and says that he can just enjoy the time at his sister's house. The next evening, Eun Yi walks home and she finds a large box in front of her home. She looks inside and sees In Ho. She brings him into her apartment and takes care of his injured arm. She then asked what he was doing here since he was only supposed to stay for that one night. In Ho said that he could pay rent. Since her brother wasn't staying at her apartment anymore, she angrily tried to contact him with no luck.
Not wanting In Ho to stay with her, she attempts to scare him off. She says that she'll only let him stay if he pretends to be her dog (since she was considering on getting a dog like her old dog, Momo). Thinking that he'll leave since no one would want to act as a dog, she feels relaxed. In Ho, needing a place to stay, immediately gets on all fours and actually pretends to be a dog. This scares her and she tries to kick him out but he wouldn't leave. So for the time being, In Ho becomes Eun Yi's dog. She names him Momo for the time being and takes care of him also. He also has to listen to everything she says. They begin to become more comfortable with one another. This human Momo reminds her a lot of her old dog. Momo was just as kind, comforting, and always there for her like her old dog. Eun Yi's first love, Cha Woo Sung, comes back. He shows interest in her and she shows interest in him. As they get along, In Ho began to feel jealous.
When Woo Sung found out that the "Momo" Eun Yi spoke so fondly of was actually a human, their relationship ends. In Ho felt a bit guilty and asks her to watch his last performance before he goes to another country as the musical choreographer. She does.However, she decided that she actually had feelings for this Momo and went to go find him, she found out that he had already boarded the plane and left. She continues on in life with her co-workers believing that her dog had ran away. Her personality had changed for the better also as co-workers started getting along with her more. Then one day, when she went to open the taxi door, someone else did the same. It was In Ho. She immediately goes into her rage and starts hitting him (like she always did when he was still pretending to be her dog) and asked him where he went. She said that he was her pet and should be loyal. He said that he was planning to call her when he came back to Korea and she got furious saying that he didn't call her back since he was already in Korea. They had a cute argument and eventually got together. As the credits roll in, on the side, they show their relationship with one another and it was really cute.
I laughed a lot throughout this movie because it was cute and funny. It was enjoyable.