When Eun-Yi arrives at her home, she walks into the bathroom and sees someone brushing her teeth. As she walks by she pats him on his rear end, assuming the guy is her younger brother Eun-Soo. When the guy turns around she’s shocked that it is a complete stranger. Eun-Soo then asks his older sister Eun-Yi if In-Ho can stay at her place temporarily, telling her that he’s really good with household chores. Eun-Yi disapproves of the idea, but that night Eun-Soo accepts money from In-Ho to stay at her sister’s place.

The next evening, on a rainy night, Eun-Yi walks home and finds a large blue box on front of her home. When she looks inside of the box she’s shocked again to see the guy the from the other day, In-Ho, sitting in the box. Ji-Eun brings sopping wet In-Ho into her apartment, while she tries to contact her younger brother. Her younger brother doesn’t answer her calls. Oddly enough, In-Ho reminds Eun-Yi of her former pet dog Momo. Eun-Yi then comes up with an arrangement. She will let In-Ho stay at her apartment if he will become her pet dog named Momo.

As they become more familiar and comfortable with each other, Eun-Yi’s first love Cha Woo-Sung (Ryu Tae-Joon) comes to her office looking for her …

Cho Dae-young is a natural detective with the highest number of arrests to his credit within his team. An elite cop who deals with the most heinous crimes, he is ordered to join the task force to crack down on the pickpockets, he is reluctant to work on the unit due to his painful past: His pickpocket mother has a criminal record spanning 17 arrests. Despite his reservations, however, he is convinced to join the team by his old friend, Lieutenant Oh. Vowing to undo his mother’s wrongs, he joins the investigations, armed with his police instinct and passion for the work.

With her Korean pickpocket gang, Baek Jang-mi begins to make big money. One day after a successful heist she is attacked by members of their rival Twin Gang, but she is rescued by Dae-young, who was investigating a case nearby. The two immediately feel an attraction for each other, but after Jang-mi discovers Dae-young is a cop, she quickly leaves the scene. Meanwhile Dae-young, while looking through some police files handed to him by Lieutenant Oh, finds out that the woman he saved is none other than Baek Jang-mi. He senses an inevitable fight looming on the horizon.

The WAIS traces of Jang-mi’s movements indicate she had been in Japan each time a huge pickpocket heist took place. Nonetheless, Dae-young goes after Jang-mi, but becomes mesmerized by her devastating beauty and feels himself falling prey to her magic…