Sherlock Holmes Investigates. The Free Trade Consortium.

Sherlock Holmes and Dr Watson uncover a well organised and substantial smuggling operation. The criminals style themselves as Free Traders, and deny Her Majesty's Government's right to levy import duties on goods.
The pair follow the trail through sewers and a church to a moonlit landing of contraband in order to discover the secrets of the Free Traders Consortium.
With the information they gather, the Revenue Department is able to interdict a considerable operation, and arrests are made.