Michael's health club is beseiged with a series of terrible murders involving killer saunas and other grisly devices. Michael's wife killed herself a while before and her brother holds Michael responsible. Michael needs to stop the bloodshed before he loses all of his clients.

Dr. Pretorius and his colleagues are working on a sensational experiment: by means of stimulation of the pineal gland, they want to open the human mind to higher dimensions. When the experiment succeeds, however, they are immediately attacked by terrible life forms, which apparently are floating around us all the time. When Dr. Pretorius is killed by one of them, Dr. Tillinghast is under suspect and thrown into the psycho ward due to his stories. Only the ambitious psychologist Dr. McMichaels believes him and wants to continue the experiment.