1960s Britain: When one of his regular snitches is found floating in the lower Thames, Inspector Jerry Carnaby is in a quandary. The dead man had arranged a meeting with him, promising vital information on a new crime.
Unfortunately, there are three distinct possibilities to sort out, and the tip could apply to any of them. It could be a large gold shipment due in from Cardiff. It also could involve a pending visit by an important German diplomat. Or it might have to do with the seemingly improbable claim of a scientist that he has discovered a means of transmuting common materials into precious metals.
Carnaby is off to a bad start when his superiors divert him from these cases to escort the diplomat's hyperkinetic daughter around London when she arrives early to do a little shopping.
When the man assigned to watch her hotel room overnight is found strangled, the threads begin to come together and Jerry finds himself searching for a faceless master thief who had vanished a decade before....