Original: 불한당
Romance blossoms between a single mom and a womanizing bad boy.
Oh-joon Kwun, a boxer who rips off girls he neets for money, needs to pay back 30 grand in interest to a loan shark company called "Cash 'N Check." Dal-lae Jin, a young widow living with her mother-in-law and daughter, runs into his car...
Oh-joon finds out Dal-lae is worth 30 grand, He uses the same tactics to lure Dal-lae as he used with Yun-ha but it doesn't work. A rich old man is also interested in Dal-lae, but for his son, Jin-goo.
Dal-lae begins to wonder if she is becoming interested in Oh-joon. She can't forget her dead husband and becomes ill near the anniversary of her husband's death. Soon-sum, her mother-in-law, wonders if she should sell insurance to thugs.
Dal-lae takes Oh-joon to a meditation center to help him get over his "loss." Oh-joon discovers Dal-lae is looking to buy a coffee shop for her mother-in-law and realizes he can use this to trick her.
Oh-joon helps a guy from "Cash 'N Check" to get his dream girl. Dal-lae agrees to teach Jin-goo to become more likeable and less awkward. Oh-joon gets closer to setting Dal-lae for the con, and Dal-lae lets Oh-joon know that she is a widow.
Oh-joon succeeds in conning Dal-lae out of her 30 grand with help from the guys from "Cash 'N Check". He begins to feel remorseful and he gets back the money to return it to Dal-lae...
Oh-joon gains Dal-lae and her family's trust after returning the money. But Jin-goo is still suspicious. Oh-joon vows to turn over a new leaf, but he finds it hard to not tell more lies to Dal-lae.
Oh-joon becomes tired of dodging questions and realizes that in order to remain truthful, he has to come clean. Before he can tell her, Yun-ha finds Dal-lae through a colleague at the bookstore and divulges all of his secrets.
Jin-goo develops feelings for Dal-lae and confesses. In the meanwhile, Oh-joon vows to get forgiveness from all the women he's conned in order to win Dal-lae back. He becomes wretched when he discovers Yun-ha committed suicide.
Oh-joon deals with his feelings of guilt. Dal-lae's mother-in-law, Soon-sum sings to get more customers for the coffee-shop when Ho-jin confesses his love for her. Oh-joon is investigated by the police.
Jin-goo tries to convince Dal-lae not to go back to Oh-joon and when this fails, he goes to Oh-joon to persuade him they are not a good match. Man-doo helps Oh-joon to get his charges dropped and Oh-joon and Dal-lae begin dreaming of a future together.
Oh-joon is shocked to discover he has a potentially fatal brain condition. Jin-goo's father has Oh-joon beaten when he won't give up Dal-lae. Oh-joon breaks up with Dal-lae, telling her he doesn't love her anymore to spare her the pain of seeing him die.
Dal-lae continues to be heartbroken about Oh-joon. Oh-joon tells Soon-sum the reason he broke up with Dal-lae to gain her support. Mandoo arranges for Oh-joon to meet a healer but he misses the appointment, helping his Cash 'N Check friend instead.
Oh-joon takes a job as a sparring partner and Man-doo becomes worried for him. He tells Dal-lae the real reason Oh-joon left her.
Oh-joon and Dal-lae get back together. Jin-goo has a sleep-over with Soon-dae, Dal-lae's daughter. Oh-joon finds out that Man-doo is gay.
Soon-sum reconciles herself to Oh-joon and Dal-lae's marriage. She also agrees to finally marry Ho-jin. Oh-joon meets his sick father, and sees his sister again. He moves in with Dal-lae and they make future plans.
