Act III. In Mary's bedroom, she tells Margaret how sweet William Ratcliff used to be, and how she is having dreams that he is a spectre reaching out to her. She asks what happened to her mother, and Margaret relates the events. Despite his injury, Ratcliff, whom Margaret mistakes as Edward, enters. Mary tends to his wounds. When Margaret intones her song again, Ratcliff goes mad and kills Mary. MacGregor, responding to calls for help, enters, and is killed by Ratcliff, who goes off to the alcove and commits suicide. The two phantoms appear and embrace. Douglas and guests enter and react to the tragedy.