Thirteen-year-old Celeste Jardine has one priority for the summer: to identify her source — earth, air, water, or fire. Only then can she register for one of the four public source schools and avoid being sent to Fluidity, the local private school for unidentified teens. Things explode the last day of school when Celeste learns that her perfect best friend, May, is going away to earth camp for eight weeks. To add insult to injury, Celeste's mom has decided to send her to summer camp at the very place she has been trying so hard to avoid ... Fluidity. Celeste resolves to try anything under the sun—or on the Internet—to get into source school in the fall. But, after rekindling a friendship with her estranged neighbor, Rainie, Celeste must confront startling new truths about who she is, who she loves, and where she wants to be when fall classes start.