First half is the story where Young-su (MC) and Sumin (FMC) who is 11-years older fall in love at first sight. MC is in this town for a 6-month assignment for his Company. Sumin is his friend, Charlie's, 'mother'. First half of story is devoted to how MC and FMC first hide their relationship. Charile's GF finds out, but helps them. There is good comedy here, as there is a redheaded daughter of company CEO who has the hots for Young-su and Charlie is trying to set his mom up with her ex, the art director. Charlie eventually finds out about MC and FMC and is convinced to be OK. Turns out Sumin is his adoptive older sister who gave up her art career to raise him after his parents died. Charlie goes off to the army. Now you would think, happy ending. But no.
Part 2 starts with introduction of a villain, Sumin's old classmate who thinks Sumin did her wrong at university. She runs a graphics company and employs MC wanting to steal him from Sumin. MC & art director convince Sumin to restart her art career and she becomes famous and embarks on a European tour. There is also stalker of MC's new boss, and the boss trying to seduce MC. MC learns of her intention and quits which makes her more mad. But now he has no job while Sumin is making big bucks. Art director tells him to break up with her because he is holding her back. He does and mopes around. Until he is remployed by a penitent ex-boss who is told by the art director that it iwas he who had changed the paintings for judges in university. Young-su shines at his job. Twist is that Sumin always knew that he had broken up with her because he felt he was inadequate for her, and was giving him time to grow some balls. Author decides that he has and Sumin comes back. There is some silly drama about a mechanic trying to assault her as she is on her way back to surprise MC. But all ends well and everyone is happy and paired off.