Dirty Laundry by Daniel Ehrenhaft

the school:

The Winchester School of the Arts, nicknamed "The Laundromat" because it's where better schools send their "dirty laundry." Get kicked out of Exeter, Hotchkiss, or Choate? End up at Winchester.

the girl:

Carli, a gorgeous pigtailed Hollywood actress going undercover at Winchester to research her role.

the boy:

Fun (short for Fellini Udall Newport), an embittered senior and graffiti artist who was almost expelled—until his dad (and a lot of money) convinced the headmaster to let him work off his crime as Carli's assistant.

the problem:

Beautiful, talented senior Darcy Novak, one of the least screwed-up people at Winchester, has disappeared.

As Carli and Fun discover each other's hidden talents, there's a villain setting them up. Can they save Darcy—and themselves—or will they wash out?