Comedy and intense drama complement each other throughout AD ASTRA. Heroic ace of Great Britain's Royal Flying Corps in World War I, Captain Elliot Parsons has come to realize how truly obscene the war and his propaganda role in it are. His sweetheart, Jennifer Stanley, has become a military nurse to help him flee the war and thus declare their "farewell to arms". Parsons, though, has been assigned a replacement to mentor, one Lieutenant Alan Owens, a very young and personable aviator whom he draws ever closer to and longs to protect even as he teaches him how to become a better pilot and killer. Without being fully aware of it, he is developing a feeling of love for Owens, and thus a triangle forms that complicates Parsons and Jennifer's plot to escape the war and their participation in it. A dogfight leads to the denouement that solves the complication which has compromised their plan to desert.