In 1776, a
mulatto sailor is marooned on an island after assaulting the wife of pirate captain Nathaniel Clegg. By 1792, Clegg has supposedly been captured by the
Royal Navy and hanged. His resting place is the coastal village of
Dymchurch on the
Romney Marsh. The surrounding countryside is home to the "Marsh Phantoms": figures on horseback who ride by night and bring terror to the village. Captain Collier and his band of sailors arrive in Dymchurch to investigate reports that the locals are involved in the smuggling of alcohol, from France. They are accompanied by the mulatto, mute after his tongue was cut out sixteen years earlier, whom Collier saved from death and now keeps as a slave. As Collier's men ransack an
ale house run by Rash and his
ward Imogène, the mulatto uncovers a hidden cellar. Ostensibly a varnish store, this is connected by a secret passageway to the home of coffin-maker Jeremiah Mipps, which serves as the smugglers' headquarters. The smugglers are led by the village parson Dr Blyss, whom the mulatto inexplicably attacks before being subdued by the sailors. That night, the smugglers succeed in transporting a consignment to a nearby windmill for onward shipment, although squire's son Harry, Imogène's secret fiancé, is wounded when he is shot in the arm by the pursuing Collier. Back at the ale house, Rash kills one of the sailors to prevent the smuggling operation from being exposed. This frees the mulatto, who leaves for the churchyard to break open Clegg's grave. Collier, who spent years chasing Clegg, becomes suspicious of Blyss when the mulatto later makes a second attempt on the parson's life. At Blyss's house, Rash finds Clegg's last will and testament. Learning that Imogène is Clegg's daughter, he attempts to take advantage of her compromised situation to rape her, but she escapes and flees to Blyss's home. There, Blyss and Harry both tell her they were already aware of her relationship to Clegg. After consoling Imogène, Harry confronts Rash but is arrested by Collier when the captain notices the young man's bandaged arm. Harry is led away to Collier's ship as a hostage but escapes when the Marsh Phantoms appear, distracting the sailors. The Phantoms, who are actually villagers in disguise, take Harry and Imogène to the church, where they are hurriedly married by Blyss before leaving to start their life together. Collier arrives at the church and announces that Clegg's grave is empty. He then tears off Blyss's collar to reveal the rope burns from an unsuccessful hanging, exposing the parson as Clegg. Clegg declares that his executioner spared his life and that he wished only to help the inhabitants of Dymchurch live comfortably. A struggle breaks out between the villagers and the sailors, enabling Clegg to flee with Mipps via the secret passageway. However, on emerging at the coffin-maker's house they run into the mulatto, who has murdered Rash and fatally impales Clegg with a spear before being shot dead by Mipps. In the film's closing scene, the villagers look on and Collier and the sailors salute as Mipps sorrowfully places Clegg's body in the open grave. ==Cast==