Lance Brant is looking for counterfeiters who are producing phony $10 and $20 bills; his father's department at the U.N. is likewise interested because counterfeiting "makes bad propaganda." Meanwhile, Bob and gang head to the National Museum to do some research in the Egyptian Room for a big school exam on hieroglyphics. Upon arriving, they find the museum closed because of mummies seen haunting the halls. Ever curious, they find an unsecured entrance and go on in for a look around. As reported in the newspapers, the museum is indeed haunted; mummies as well as knights in armor chase the boys. However, they soon discover that it is just the counterfeiting ring, using mummy costumes and suits of armor to frighten people away from their base of operations. In a major change in tactics, Bob actually telephones Lance to come and pick up the crooks once they have been captured.
Lance Brant once again investigates the unauthorized photography of secret documents, in this case, plans for an atomic pistol at a government experimental factory. He receives a telephone call from Felix Klein, the owner of Klein's Machine Shop, who reports a suspicious order. He's been asked to make a part for a toy pistol, but from impractically heavy and expensive material. Klein is murdered while on the phone with Lance, but not before telling the investigator that his friend George Breslin has gotten a similar order for a different part. Following up on information provided by Breslin, Lance breaks into the Miracle Toy Co. Most crates he examines contain simple squirt guns. In the last crate he checks, however, he finds far heavier guns that burn a hole through cement! He is discovered by enemy agents Turk and Niklos and their beautiful leader Flora, who are planning to ship the deadly weapons to the Reds in Korea, hidden among the look-alike toys. He learns that it was an employee of the government experimental factory, Dr. Mark Wells, who had photographed the plans and given them to Flora, whom he loved madly. Thanks to Lance, the plot is ruined.
As the story opens, the city is gripped by a wave of mysterious bank robberies. The police are stumped, because everyone in the bank dies horribly, but without a mark on them. Lance Brant is assigned to the case by the Intelligence Department; his father's office is also involved. Meanwhile, Bob, the Troubleshooters, and the girls are invited to a party for brilliant but mysterious classmate Roger Carstairs by his doting father, who is concerned about his son's social skills. Mr. Carstairs tells the boys that Roger has "always been a strange boy! And he's been making some new friends, lately...older men...and I don't like their looks! He needs good wholesome friends." When Bob gets a look at one of these new pals, and realizes the man is a member of the criminal gang they battled previously, led by that master of disguise, False Face! Bob and the Troubleshooters confront Roger about his poor choice of friends, and the cold-hearted teen boasts that he is indeed behind the bank robberies. He tells the gang, "I am a super being...A new step up in man's evolution...I have powers you petty mortals never dreamed of!" Feathers adds, "Roger is a mutation, a super-being, with intellectual powers far beyond our present day understanding! ...Roger...has turned his mutant powers toward evil, in a world of people he despises!" Roger's power? He can create images of big swarming insects in people's heads. The sensation of being attacked by these horrible creepy-crawlies is more than the human mind can handle and his victims die of sheer fright. Once a bank is cleared of potential witnesses, he sends in False Face and his gang to grab up the money for him. Roger's father debates killing his obviously evil son, but False Face gets him off the horns of that dilemma by obligingly gunning down the kid before making his escape. Once again, the role of Bob and the Troubleshooters remains unknown to Lance and the authorities.