The Atomic City

Frank Addison, a physicist working on top-secret projects, and his wife Martha raise their young son Tommy in Los Alamos. Tommy goes with schoolmates to Santa Fe for a carnival, accompanied by their teacher Ellen Haskell.

During a puppet show at the Santa Fe carnival, Tommy vanishes without immediate notice. The search intensifies when his name is announced as the raffle winner for a bicycle. Frank and Martha fear something sinister has happened and await a phone call.

They receive a ransom note assembled from words taken from different newspapers. A phone call instructs them to stay silent.

Ellen, whose boyfriend is FBI agent Russ Farley, passes along her concerns to him. Farley and his partner Harold Mann begin tailing the Addison family to monitor the kidnapper's movements.

A small-time thief, David Rogers, collects an envelope containing the file at a post office. The FBI follows him as he carries the package toward an unknown destination. The pursuit marks the early steps of the investigation into the kidnapping.

Rogers heads to a baseball game, with the FBI requesting TV cameras to zoom in on him. After the game, his car explodes, killing him, and the envelope is missing. The FBI suspects he passed the file to someone at the game.

The FBI reviews the game footage and spots a hot-dog vendor who is actually Donald Clark, a man with Communist ties. They bring Clark in for questioning, but the information they extract is limited.

Dr. Addison is left in an adjoining room and confronts Clark, beating him to force a confession about Tommy's whereabouts. The confrontation confirms that Tommy may be in Santa Fe or nearby, intensifying the chase.

Tommy is moved by his captors to Puye Cliff Dwellings in New Mexico, where they briefly encounter the Fentons, a family of tourists. The remote location increases the stakes as both the FBI and captors converge.

The mastermind Dr. Rassett studies the mailed file Addison mailed and determines it to be a fake. He orders Tommy killed to prevent exposure, escalating the danger.

Tommy escapes from his captors and hides in a cave, evading pursuit. He remains hidden as the adults close in, unaware of his exact location.

The Fenton family's son finds the raffle ticket on the ruins and brings it back to Santa Fe to exchange it for the prize. With the area under FBI watch, agents seek to determine where the ticket originated and quickly learn Tommy's whereabouts.

The FBI converges on the site and Rassett is arrested after killing his accomplices. Tommy is rescued and the threat is ended.