A nearly deserted carnival is the scene of espionage, and murder. Steve Mitchell is dispatched to Zuric Switzerland to learn what he can about the lost contact at the carnival. What happened to Bruner? While he waits for the secretary to arrange a meeting, Steve checks out the carnival attractions. Max Raver is a sharp shooting carnival manager, but his meeting with Steve could turn out to be a trap.
Later, in the police station, Steve revives from his thump on the head. The police inspector is doubtful as the account is reviewed, along with a matter of an over enthusiastic cab driver named, Karl Hansen. After reporting in to the home office, Steve continues to explore who he can trust, and who he can’t. Coming full circle, Steve is in time to break up a fight. and rescuesMax.
While snooping, Steve allows himself to be captured, and have Max rescue him. Where has he been taken? Bruner’s true identity is discovered, and could be surprising. But Steve has the last word in being a razzle dazzle artist in retrieving File 307.