In March 1943, a woman named Dorothy McKibben gets a job as Oppenheimer’s secretary. She finds herself managing the influx of scientists to Santa Fe, issuing them security passes, giving them instructions on how to behave in town, and providing them directions to Los Alamos. She becomes known as “the Gatekeeper.”

Other residents notice all the strange new people, along with the parade of Army trucks going up the canyon toward Los Alamos. They guess that the government is working on a secret project—a new submarine, a death ray, a hideout for pregnant military workers, etc. Fearing a member of the public might stumble onto the truth and leak it to the Germans, Oppenheimer calls in Charlotte Serber, wife of his chief assistant, physicist Robert Serber. He asks her to plant a rumor in town that Los Alamos is where the government is building an “electric rocket.”

The Serbers go into town, visit bars, act a bit drunk, and loudly announce the electric rocket program. No one takes the bait; Army intelligence and the FBI hear nothing about the rocket from their informants. Locals do continue to apply to the Gatekeeper for jobs with the mystery program.