On a weekend trip to the fictional Edwards Island, teenager Alex arrives for a beach party with her new stepbrother Jonas and her friend Ren. Once there, they meet two other teens and learn about the island's history as a former military site. While exploring the caves, the group hears that certain radio frequencies are rumored to trigger strange events, and when Alex tunes her radio to an unusual signal, she unexpectedly opens a rift and unleashes a paranormal force. As the night takes an increasingly eerie turn, Alex and her friends must work out what they have awakened and how to set things right.