A "sweet sixteen" party is supposed to be among the most memorable events of a girl's life. But on the night of her party, Mercy Clare wakes up in the waiting room of a hospital with no memory of how she got there. To make matters worse, she's wearing something she would never be caught dead in: her best friend Lyla's clothes. Mercy's nightmare is just beginning. The doctor tells her, referring to her as Lyla, that Mercy is lying in the hospital bed...