Department S

Four men in costumes are gunned down in a cellar while celebrating a successful crime. When the bodies are found, the police discover that one of them had a recently fired gun in his holster - yet no crime had been reported at the time in question. Sir Curtis suspects that a criminal named Martin Kyle is somehow involved, and tells Stewart to pay him an 'unofficial' visit.

Stewart uses a mixture of coercion and trickery and gets some useful information out of Kyle. That evening, when Kyle is supposed to meet the man he got his assignment from, Stewart and Jason 'drop by' again. While the man gets away, he leaves behind a WWII marshal's baton, which the investigators subsequently use as bait to flush him out, although they still don't know what the baton's significance is.

The case gets more complicated when they find a car dumped in a lake and an unidentified body inside and discover that the ballistics match the gun found with the dead man in the cellar. Now they have to connect the dots between the dead man, an unreported robbery, and a young woman kept prisoner in her own house...