The testimony of the hanged man

Inspector Ben Ross is summoned to Newgate Prison by James Wills, a man about to face the gallows, Ben is shocked to hear his account of a brutal murder that he witnessed on Putney Heath, sixteen years ago. Unable to halt Wills's execution, Ben is ordered to forget the matter and instead to investigate the abduction of a wealthy London gentleman's wife and child. Meanwhile, Ben's wife Lizzie, and her maid Bessie take a trip to Somerset House followed by a cab ride to Putney Heath that convinces them that the testimony of the hanged man was true and a murderess is roaming free.