Jane Jarvis and Allison Concord are desperate to get through senior year at St. Teresa's Preparatory School for Girls, where barbed wire keeps the boys out and the ancient nuns keep the girls in.

Jane and Allison have always been too quirky and different to be popular, but at least they've had each other. Then, after a hideous, embarrassing disaster, Allison comes to school transformed. Suddenly she has cute hair and clothes. She's fluent in Latin, she won't even speak to Jane, and within days she's stolen Jane's ex-boyfriend, Elton.

A strangely wise freshman boy, Owen, helps Jane discover the outrageous truth--that Allison has sold her soul to the devil. At first Jane doesn't quite buy it. She plays along with the weirdness--and even gambles her own soul in order to rescue Allison. But events take a turn for the real, and Jane will have to save Allison before the bizarrely exclusive Poodle Prom, a party of biblical proportions that just might blow apart the world as Jane knows it.