My Name is Kim Sam-soon is about a slightly overweight pastry chef who gets unceremoniously dumped by her boyfriend on Christmas Eve. Nearing 30, with no college degree, no boyfriend and no job, her prospects do not look very bright. However, for Kim Sam-soon, outspoken and foul-mouthed, she refuses to bend to society's expectations. Things take an unexpected turn when she agrees to a contract relationship with her new boss, restaurant owner, Hyun Jin-heon to both help her family out of their money troubles and him out of his mother issues. Early on in their relationship Sam-soon dubs Jin-Heon 'Sam-shik' when he unsuccessfully tries to keep her from going by another name, 'Hee-jin,' at the restaurant where she works for him. Sam-soon's name, which can be translated literally to third daughter in English, has been one of the many things that she finds a source of embarrassment to herself (along with her age, weight, and single status). She would love to change her name, but if only her mother would agree to it. Jin-Heon is the son of a wealthy hotel president and uncle to his orphaned niece, Mi-joo. His mom insists he find a wife before his niece begins kindergarten so Mi-joo will have a mother at the parent-teacher conferences. (Silly moms.)

When his mom mistakenly believes that Sam-shik and Sam-soon are dating, Sam-shik suggests they continue the ruse so his mom will back off. Sam-soon balks at first then grudgingly agrees to pretend to date him for appearances in return for a loan of fifty million won to help out her family. It's a hesitant partnership at first which would have bloomed quite smoothly into something more (which it did, but not quite so smoothly) had it not been for Sam-soon's ex, Sam-soon's ex's fiancée, Sam-shik's ex, Sam-shik's ex's young and handsome doctor, their mothers, their mothers finding out about the fifty million won, their stuffed piggy (Sam-sook), Sam-shik's temper, Sam-soon's right hook, and karaoke night.