Hayley Atwell reprises her role as Carter from the film series, and is joined by regular cast members James D'Arcy, Chad Michael Murray, Enver Gjokaj, and Shea Whigham.
Recurring guest stars Ralph Brown and Bridget Regan portray the antagonists, Johann Fennhoff and Dottie Underwood, while Dominic Cooper and Toby Jones reprise their respective roles from the film series as well.
Howard Stark returns and explains that he had developed the gas, named Midnight Oil, to give American soldiers extra stamina during war, but it caused psychosis and led to them killing each other.
[1] In February 2015, Marvel revealed that main cast members Hayley Atwell, James D'Arcy, Chad Michael Murray, Enver Gjokaj, and Shea Whigham would star as Peggy Carter, Edwin Jarvis, Jack Thompson, Daniel Sousa, and Roger Dooley, respectively.
[1] It was also revealed that the guest cast for the episode would include Lyndsy Fonseca as Angie Martinelli, Ralph Brown as Dr. Ivchenko / Johann Fennhoff, Dominic Cooper as Howard Stark, Bridget Regan as Dottie Underwood, Walker Roach as "Captain America" radio actor, Erin Torpey as "Betty Carver" radio actor, Ralph Garman as radio announcer, Dajuan Johnson as Officer Pike, Glenn Taranto as Detective Prendergast, Kevin Ashworth as Agent Fisher, Patrick Smith as Agent Butch Wallace, Matt Raimo as Reporter #1, Ward Roberts as Reporter #2, John Prosky as Senator Walt Cooper, Gerald Webb as Prison Guard Gary Trower, and Christopher Poehls as Ground Crewman.