In the strenuously guarded atmosphere of Project Blast it seemed almost impossible for highly secret microfilm to disappear. Yet to the utter dismay of Doctor Kendall and his close associates as well as to his eleven year old son Sammy, a spy had apparently infiltrated the operation. Sammy's keen deliberations bridge the gap between the traitor and a house prowler who had obviously been in the vicinity of his carrier pigeon loft, and, increasingly, the Stepneys (alias Stepanovich) very decent neighbors, fall under suspicion. The F. B. I. man stationed at the Kendall's pursues this line of reasoning to discover that a carrier pigeon had been brought into the research center and sent out equipped with microfilm. A property search including the pigeon loft and a chase during an exciting dinner party at which all suspects are present reveal the culprit as well as his ingenious cache for the goods, the empty eye-socket of Doctor Kendall's mounted moosehead. Mental maneuvers do not point any obvious finger as with Sammy we piece evidence together bit by bit, through to the harrowing conclusion. Stylistically terse, intelligently written, we are held from beginning to end.