When Roger and Rachel Mowbray arrive at the desolate cliffs of Slyne Head for their honeymoon, they expect only wild scenery and the company of their eccentric friend, Dr. Gramery. But the Doctor’s fascination with hypnotism is more than a parlor trick; it is the instrument of a cold, decades-old vengeance against Roger’s family. As the tide rises in a remote sea-cave, Roger faces a terrifying test of the senses. Can he break the spell and see the truth before the water claims his wife, or will an old enemy’s power force him to abandon her to the waves?