When fifteen-year-old Rachel Bennett goes to work at her uncle's veterinary clinic in Agatha, a dusty prairie town, she predicts an uneventful summer. But the reality turns out to be quite different. She soon falls for sixteen-year-old Michael Bell, and the attraction is mutual and immediate. The boring summer she's been expecting is suddenly looking exciting.

And then her new beau's painful past begins to get in the way. Michael's life has been torn apart by the death two years earlier of the older brother he idolized. Despite his affection for Rachel, he can no longer hold his frustration and anger inside and he begins to strike out at the people around him.

For years, Michael and his friend, Scott, have been at odds with Cory and Taylor. In the past, the four boys have amused themselves by exchanging insults. But this summer, things begin to spin out of control, and Rachel finds herself caught in the middle of a series of increasingly violent pranks that threaten the stability of the small community and force her to question the boundaries of friendship and trust.