Esther Solar's family is . . . unusual. Her father hasn't left the basement in six years. Her brother is terrified of darkness. Esther isn't afraid of anything - because she avoids pretty much everything. Elevators are off limits, as are open spaces, crowds, family pets, birds, needles, haircuts, dolls and mirrors.

But when Esther is pickpocketed by her cocky old classmate Jonah Walker, Esther and Jonah become surprising friends. Jonah sets a challenge: every week they must work their way through the world's fifty most common phobias. Skydiving, horse riding, beekeeping, public speaking, reptilehouses - they plan to do it all.

Soon their weekly foray into fear becomes the only thing that keeps them tethered to reality, and to each other. But each is keeping a secret from the other, a secret that threatens to rip them apart.