While on vacation in the town of San Soros, Alexander hears the legend of the island just offshore. Hundreds of years ago, the townsmen killed almost all the women as witches, but the women still remain, the angry and vengeful undead. They destroyed the island monastery in revenge, and for a man to go to the island is death. Every year, the villagers appease the ghost women with gifts of flowers and beads ... but every hundred years, the legend goes, a man must be sacrificed.

Alexander doesn't believe a word of it. When village woman Lucia and fellow tourist Nettie ask him to accompany them to the island, he agrees. There Lucia drugs him, and both she and Nettie leave Alexander alone on the island, rowing back to shore. Alexander takes refuge in the ancient church, intending to try to get back to the mainland tomorrow.

Unfortunately, the legend is real. The undead mermaids return and take their due. The tithe is paid for the next hundred years.