Na-rae moves to Seoul to begin a new life of independence, leaving behind the comfort of her childhood home. Hoping to start over, she takes her first steps into adulthood and the unfamiliar city life. What she doesn't expect is that her new beginning will place her in the same apartment building as her ex from college-Sim Jaeyun.

Se-rin has spent her entire life striving for the validation of her busy parents. When she accidentally wanders into a dangerous part of the city, she crosses paths with Sunghoon, a guy who grew up facing trouble and run-ins with the law. At first glance, they are total opposites: the perfect daughter and the troubled bad boy. As their two worlds collide will they clash, or will they find they have more in common than they ever thought?