For 25 years, Jaein/Jenny has been the only child. Running away from her dad and his new family, she then takes refuge in Korea. She will have to face the fact that she's now a big sister to immature Jude. 

He's the reason i find men are disguisting. He's the reason why i've never been kissed.. but he's my last chance.

She's plain while he's hot. he's single while she's engaged. is there a chance for them?

Minji was given a chance to start a new life but she never expect that the past is haunting her.