Frannie O'Neill is a young and talented veterinarian living in Colorado. Plagued by the mysterious murder of her husband, David, a local doctor, Frannie throws herself into her work. It is not long before another bizarre murder occurs and Kit Harrison, a troubled and unconventional FBI agent, arrives on her doorstep. Late one night, near the woods of her animal hospital, Frannie stumbles upon a strange, astonishing phenomenon that will change the course of her life forever....