The Case of the Dixon Torpedo

Between ten and twelve on an ordinary morning, one of only four sets of drawings for a new naval torpedo vanishes from a drawer in a Chancery Lane office. Nobody came in past the barrier; nobody went out. The inventor faces ruin and a broken Admiralty contract if the design reaches a foreign buyer, so he brings the problem to Martin Hewitt, who begins not by questioning the two draughtsmen but by leaving a door ajar and watching the outer office.

Hewitt arrived just after Sherlock Holmes went over the Reichenbach Falls, and was built as his opposite: affable, ordinary, patient. Recovering what has been taken will require him to step well over the line of the law.