While in London trying to nab several fugitives who stole a million dollars from a U.S. Treasury vault, American federal agent Dennison (Dennis O'Keefe) assists Scotland Yard Insp. McClaren (Philip Friend) in his search for a missing atomic scientist (Paul Hardtmuth). The detective duo discovers that the key to solving both cases may rest with the scientist's daughter (Margaret Sheridan) and her fascinating diamond.
This has something of the "Rumpelstiltskin" to it, only it's not straw into gold, it's sugar into diamonds! "Dennison" (Dennis O'Keefe) is on the trail of some thieves who stole a fortune in US treasury bonds and are heading to London to do a deal with the gem fakers. His arrival sees him allied with "Insp. McClaren" (Philip Friend). This policeman is also working on a more sensitive case involving a nuclear scientist - and it just so happens that his daughter "Marline" (Margaret Sheridan) is wearing a brooch with one of the Wonka-jewels in it. As we discover who made it, the threads of the story start to come together - but who is pulling whose strings? It's a bit long and takes a while to get started, but once the wheels are in motion it's not a bad little thriller with some magical science (courtesy of Paul Hardtmuth) and a bit of menace from the usually reliable Francis de Wolff. It's all production line stuff with themes based on already well used, adequate acting and predictable plot-lines , but it is watchable enough.