After a million dollars is stolen from a treasury vault, the trail takes O’Keefe to London and with the assistance of Scotland Yard, they attempt to break up the racket. He and Philip Friend, the British detective he is teamed with, hit it off right out of the departure gate. They are always on the same page, each having an eye on Sheridan. The film is a procedural account of the authorities trying to find who is behind the profiteering from the sale of synthetic diamonds.
Sheridan transferred to a London hub to be with her father, a renowned atomic scientist, busy making synthetic diamonds for industrial research in a spooky mountain top castle rented from Dr. Frankenstein. The process is a dangerous mix of towering flames, giant dials, lights and switches. These laboratory scenes are in stark contrast to the mundane search by O’Keefe and Friend. A few abrupt edits back and forth between the scenes can be jolting and irritating. O’Keefe’s accumulating evidence suggests the scientist’s integrity may be in doubt. Sheridan refuses to believe it.
The film is a routine investigation with a slow beginning, but it is nonetheless an entertaining effort. Starring less competent actors, there might be a channel change in the first thirty minutes. But hang on for a worthwhile explosive ending.
Note: A couple of scenes to mention. One, in a later Peter Yates style, has O'Keefe at the top of an escalator returning fire at a criminal holding a drawstring bag full of fake diamonds. The thief first falls backwards but the escalator slowly brings him back to the top as the diamonds spill out of his bag and roll to O’Keefe’s feet. Another is the filming of a ship's funnel as her steam whistle blows. Clever if not original, the camera then pans backward to reveal simply a model on the bridge of the real ship they are on.