Looking at the style of this production, you wouldn't really have to guess it was based on characters originally created for the wireless. The production is very precise, static almost as we witness the eponymous amateur sleuth (Anthony Hulme) try to get to the bottom of some diamond thievery and of the mysterious death of a police constable working on these heists. Along the way he enlists the help of the dead man's girlfriend - a journalist who uses the moniker "Steve" (Joy Shelton) and pretty soon they are embroiled in a clever and dangerous plot hiding in plain sight. What does make this work is the writing - the story requires us to engage our own grey cells a bit if we are to get any satisfaction from the otherwise rather pedestrian presentation. We are given some clues, some red herrings and the actors sort of act as guides as we try to solve the mystery for ourselves. I reckon this would have worked just as well on the radio, but on film it is an enjoyable enough mystery that over-stretches a bit long - at eighty minutes - but is still worth a watch.