An outlaw with a price on his head, Gideon Viscount St. Mars accepts a risky commission from James Stuart, the Pretender, in the hopes of regaining his estates. Back in England, however, he finds Mrs. Kean entangled in a nest of Jacobite spies. When one of them is murdered, Gideon must choose between his allegiance to James and his concern for Mrs. Kean before uncovering the killer.