Dark Shadows - Season 10 Episode 46 : DS-1106 1971

Julia and Willie find that Roxanne is the vampire, they decide to chain the coffin instead of destroy her. Sebastian goes to Roxanne’s coffin, but finds it missing; Willie and Julia has moved it to the Old House. Julia tells Barnabas that Roxanne is the vampire. Barnabas releases Roxanne, she attempts to attack him, Willie chains the coffin again. Later Sebastian opens the coffin and prepares to shoot Roxanne.