The security apparatus cranks up in the latest episode of Manhattan as someone in Winter's group is accused of being a Communist, phone calls are monitored, and someone tries to get laid. Spoilers ahead.
Physicist and beard master Glen Babbit comes under suspicion of being a Communist due to an a claim that he secretly associated with a scientist who defected to the Soviet Union. While the Soviet Union was an ally during World War 2 many people thought they would be the main threat afterwards. Of course the Soviet Union did have spies in the Manhattan Project so the concern was not unjustified.
Unfortunately Babbit can't reveal the truth. I don't think the word is actually used in the episode but Babbit is a closeted homosexual who was in a relationship with the defector. His homosexuality would be sufficient grounds to lose his security clearance (ostensibly because it makes him at high risk for blackmail). So he has to stick to his lie of not knowing the defector.
Enter Frank Winter, who has something on Babbit's main accuser Charlie Isaacs. Winter can't just confront Isaacs, he has to mess with him through his wife who works at the base switchboard. Since part of her job is to listen in on calls, the wife hears Winter's accusation of plagiarism and now has some doubts about her husband. Winter's blackmail works and Babbit is cleared.
And to add to Frank Winter's unlikeability, he's cheating on his wife with the maid. Someone (presumably the government) is keeping an eye on him and knows about the affair.
Meanwhile Liza Winter can't get published because of censorship rules at Los Alamos and someone killed her bees (does Nicolas Cage have an alibi?). Fritz wants to have sex and Helen helps him out…by hooking him up with one of women on base who will have sex for a price. Is Helen just a nice person or does she get a referral fee?
Historical note for the episode: Size and weight were major issues with the Thin Man design as shown. Even the final Thin Man design couldn't fit on an unmodified B-29 bomber.