Scientists Crawford Tillinghast (Jeffrey Combs) and Edward Praetorius developed the Resonator, a machine that causes humans to see invisible creatures that live all around us, but which also allows them to see us! After destroying the machine, Tillinghast returns to the lab with Dr. Katharine McMichaels (Barbara Crampton) and Bubba Brownlee (Ken Foree) to recreate the experiment, as a means of unlocking what really happened the night that Praetorius disappeared.