To stop the wave of chaos, King George II sets up the first professional police force named the Bow Street Runners, under the command of the bellowing Sir Roger Daley, and seconded by Captain Desmond Fancey and Sergeant Jock Strapp.

The exception is the notorious Richard "Big Dick" Turpin, a highwayman who has evaded capture and succeeded in even robbing Sir Roger and his prim wife of their money and clothing.

The Bow Street Runners nearly succeed in apprehending Turpin and his two partners in crime, Harriet and Tom, one evening as they hold up a coach carrying faux-French show-woman Madame Desiree and her unladylike daughters "The Birds of Paradise."

Outraged by Strapp's incompetence, Captain Fancey travels with the sergeant to the village of Upper Dencher near to where the majority of Turpin's hold-ups are carried out.

Strapp and Fancey send a message to Sir Roger about the birthmark, and are accosted by a disguised Harriet who tells them to meet Turpin that night at ten o'clock.

However things fall apart when the rector's housekeeper, Martha Hoggett begins to put two and two together when Mrs Giles, apparently sick and used for a cover-up story for Dick's raids, is seen fit and well at the church jumble sale.

With the net tightening, the Reverend Flasher gives an elongated sermon before outwitting his would-be captors and making a speedy getaway, with Harriett and Tom, across the border.