American honeymooners in Hungary become trapped in the home of a Satan-worshiping priest when the bride is taken there for medical help following a road accident.
Oliviero is a burned-out writer, living at his estate near Venice, his dead mother dominating his imagination. He is also a degenerate: sleeps with his maid and his ex-student, hosts Bacchanalia for local hippies, and humiliates his wife Irina in front of strangers. She lives in terror. When a young woman is murdered, police suspect Oliviero. Things get complicated when his young, beautiful, and self-confident niece, Floriana, pays an unexpected visit. A silver-haired stranger observes. More women die, and thoughts of harming Irina give Oliviero new inspiration. What's Floriana's game and who's the observant stranger? Watching all is a black cat named Satan.
Specialists gather in a top-secret facility to investigate a series of strange deaths on beaches along the Atlantic Ocean. One of the team's scientists (Nana Gouvea) examines video evidence to uncover a possible parasitic explanation for the fatalities. But when a determined detective (Tom Sizemore) sends her the crazed writings of a mysterious homeless man (Jonny Beauchamp), the scientist slowly learns that the actual threat may be more dangerous -- and far older -- than anyone ever imagined. Can she convince her colleagues (led by Eric Roberts) of the true danger before an ancient force rises from the sea to bring madness and death to all of humanity