Meanwhile, several other young women in the town go missing. Her dismembered corpse is found by local children after it washes up on the shore. Later, Barbara is attacked while swimming on the beach and killed in what appears to have been a shark attack. Among them are a portrait of a saint and a serpentine creature, which predates Christianity. Madeline visits a convent on the island where she speaks with Sister Elena, and confides in a number of bizarre paintings she has uncovered after stripping the paint from the walls of the monastery. When Sherry gifts Madeline an expensive perfume, Madeline pours the entire bottle over her body. While Neil and Sherry visit the beach the next day with Madeline, Frye, and Barbara, Sherry observes Madeline acting strangely, in a seemingly trance-like state. Inside, Frye gets drunk and uses a homemade bomb to unseal a walled-off tunnel which bears a sigil engraved above it. Later that night, Frye and Madeline's friend, Barbara, use Neil and Sherry's boat to visit a remote area of ocean off the island where Frye scuba dives into an underwater cavern. They find her in the company of Frye, a middle-aged treasure hunter who is initially hostile toward Neil. While touring the island, Neil and Sherry see Madeline walking along a rocky hill, and follow her. Upon arriving on the island, the couple are met by Nereus, the elderly mayor. Neil and Sherry Grice, a young American couple, are visiting Greece in search of Neil's missing sister, Madeline, an artist who traveled to a remote island off the coast shortly before her disappearance. and the writer/producer of the film, Nico Mastorakis. However, as per The Copyright Office, copyright is registered under Omega Entertainment, Inc. It has been misconstrued as a public domain film and pirated by many distributors who copied it from DVDs. The film is also known as Bloodtide (in the US) and Demon Island (American TV title).

Its plot follows a young American couple visiting a Greek island where the husband's sister disappeared they soon find that an ancient monster has been released, forcing the villagers to return to the practice of human sacrifice to appease it. Blood Tide is a 1982 British horror film directed by Richard Jefferies, and starring James Earl Jones, José Ferrer, Lila Kedrova, Mary Louise Weller, Martin Kove, and Deborah Shelton.

The Bloody Tide by Jane Yolen