Despite a premonition of danger and feelings of personal conflict with her boyfriend Brad, Sarah Davies is determined to enjoy her family's reunion during the Fourth of July weekend. But the festive atmosphere just outside of Bearsfield, Idaho turns tense when five-year-old Joey, her cousin who suffers from severe autism, disappears from the picnic site.

Sarah and her friends join the emergency volunteers to search for Joey before an unexpected summer thunderstorm breaks loose. Joey, partially deaf and driven by fear, doesn't realize danger and he's running scared. Undeterred, Sarah, along with Meagan, Brad and Ali, search relentlessly for him. They find clues that lead them deep into a forest and eventually to the consuming river of raging waters.

None of them are prepared for the dangers or the challenges that await them, and nothing scares them more than the fear that they won't be able to get to Joey in time.