“Welcome, sir, to the Marlock Works, where we are excavating the nearby quarry. What’s that, you want to try out our remote blasting equipment? Well, you can press that switch there, but nothing will happen as we haven’t loaded any explosives. Yes, that did sound like an explosion to me. How strange, that shouldn’t have happened. But it’s Saturday afternoon. Nobody would have been in the quarry so no harm done, sir. Probably…”

When the body of the works manager is dug out of the debris, questions are raised about what happened, but at the end of the day, it was probably an accident, admittedly one that causes the man who had some responsibility for it to hang himself. That might have been the end of it, were it not for the somewhat nosey Everard Blatchington and the persistent Superintendent Wilson of CID…