When Sir John Fielding is ordered to go to the seaside town of Deal where smuggling and corruption are rampant, his ward Clarissa accompanies him and Jeremy. Strange happenings in the home of their host, the largest landowner in the area, Sir John becomes concerned. After prisoners they have taken are freed resulting in a murder, he relocates to the home of Bertie Sarton, the magistrate he was sent to investigate. When Mr. Sarton is murdered, Sir John becomes acting magistrate he plans his attack on the smugglers in which Jeremy acquits himself very well. John Bilbo, captaining his newly refurbished ship also plays a leading role in the attack.