Best friend's brother. Sister's best friend. They both have one thing in common: Off limits. Jace Lightwood. Clary Fray. They both have one thing in common: Enemies. Love. Hate. They both have one thing in common: A thin line. So what happens for Clary when off limit enemies find that thin line? Of course, without a doubt, The Best Friend's Brother Dilemma.

Clary goes to college at The Institute. Her roommate is Isabelle. Clary comes face to face with Jace, helping his sister move in. It's apparent the semester would be tough, when Jace recalls Clary's high school nickname, Dumpster Girl, a name he gave her when he bullied her. Unsurprisingly, Clary is stubborn to forget their past, but Jace is looking to move forward. Can they?