The Iron Ceiling is the fifth episode of the first season of the television series Agent Carter.
Peggy Carter is finally trusted with a mission and calls upon her trusted Howling Commandos squad for backup. But her cover could be at risk when SSR Chief Roger Dooley also sends Agent Jack Thompson with her.
In Belarus, Russia 1937, a young girl named Anya is awakened when the handcuff connecting her to her bed is loosened. She quickly finds a piece of bread she had hidden and eats while the adult is awakening other girls. Anya sees another girl and shares her bread with her; the two smile.
The new friends watch a movie in a classroom and repeat its words to learn English. Later, the two spar against each other. However, Anya is not as strong as her friend and is put in a stranglehold. When the school's headmistress nods her head, Anya's neck is snapped.
Seven years later, Anya's killer now calls herself Dottie Underwood and asks her new friend Peggy Carter for help touring New York City as they share a breakfast bagel at L&L Automat. Underwood purposefully knocks Carter's purse on the ground, and apologetically puts its contents back inside, with the exception of Carter's apartment room key.
Carter goes to work to learn that the Remote Typewriter wrote a message. Carter translates the message when the code breaker from Arlington cannot and asks Chief Roger Dooley to allow her to join Jack Thompson's team as they go to Belarus to investigate the connection to Howard Stark. She is initially refused, but when she manages to have the 107th regiment meet and escort them across enemy lines, Dooley relents and allows her to tag along.
While she is changing for the mission in the men's locker room, Daniel Sousa notices that Carter has a gunshot wound on her shoulder. This wound matches the wound of the blonde woman in the picture from La Martinique.
The 107th regiment is none other than the Howling Commandos, the unit specifically created by Captain America to fight HYDRA during World War II. As they share war stories, Thompson is asked to discuss how he became a war hero. Thompson tells the story of how he caught four Japanese soldiers sneaking into their camp and how he killed all of them before his soldiers woke up, his actions later earning him a Navy Cross.
When the team infiltrates the Red Room Academy, they find a movie projector which shows films filled with subliminal messages. They also discover a little girl; she stabs Dum Dum Dugan and shoots and kills Junior Juniper before escaping.
The team goes deeper into the compound and find scientists Nikola and Ivchenko, who are being held and forced to build a weapon from Stark blueprints acquired by Leviathan. Carter frees the prisoners, but, in the ensuing firefight with Leviathan operatives, Nikola holds Happy Sam Sawyer hostage hoping to trade him for his freedom. Strategic Scientific Reserve agent Mike Li is killed and, tearfully, Ivchenko kills Nikola. Meanwhile, Thompson freezes and is too scared to help in the shootout. Carter rescues him and they escape with Ivchenko.
As Carter bids farewell to the Howling Commandos, Ivchenko decides to go with her to the United States, claiming that he has nowhere else to go and that he would like to help the SSR stop the schemes of Leviathan.
Meanwhile, Underwood enters Carter's room in the Griffith Hotel and steals her Sweet Dreams Lipstick and a picture of one of Stark's inventions, which Peggy kept hidden under a false bottom in her drawer. She also notices a photo of pre-serum Steve Rogers and attempts a British accent, calling herself Peggy Carter.
Meanwhile, Dooley approaches Edwin Jarvis about to discuss a fist fight Howard Stark had with a general the day after the Battle of Finow, a fight which caused the general to resign and Stark to give up a six-figure military contract. Jarvis claims to know nothing about the incident, but Dooley gives him a card with his phone number, telling Jarvis to tell Stark that the SSR isn't hunting for them; rather, they simply wish to know the truth.
On the plane ride home, Thompson tells Carter the truth about how he became a war hero; the Japanese who entered their camp were holding a white flag of surrender, and that he only noticed the flag after murdering them. In order to hide his actions, he buried the flag. He reveals to Carter that he's been struggling to talk about his actions ever since he came back from the war, and Carter assures him that he just did.
Back in the office, Carter and Thompson report their mission to Dooley, Thompson praising Carter's work. Dooley tells him to call in Ivchenko as he heads out, and personally congrats Carter on her work. After seeing Carter in action and as thanks for saving his life, Thompson invites Carter to the bar with all the other men. Carter, glad to be finally accepted, agrees. She attempts to invite Sousa, but Sousa declines. As she leaves, Sousa pulls out the photo of the blonde woman, who possesses the same gunshot wound that Carter has.
Back at the Griffith Hotel, Dottie Underwood handcuffs herself to her bed's headboard before going to sleep.