On a moonlit night in Los Angeles, something darting out of the shadows causes siblings Ellie (Christina Ricci) and Jimmy (Jesse Eisenberg) to suddenly swerve their car off the road and plunge into a ravine. They escape with their lives, but are forever changed by the accident. Suddenly, the career-driven Ellie and scrawny Jimmy find themselves blessed with increased physical strength, heightened sensibilities and undeniable allure to everyone around them.
But what happened to them that night wasn't just an accident and what seemed like fate was really something more. New impulses are taking over and Ellie and Jimmy can no longer control their newfound powers. They must solve the mystery and break the curse before it completely consumes everything in its path.