In an alternate 1939, giant robots descend upon New York City, wreaking havoc and instilling terror. Amidst the chaos, intrepid reporter Polly Perkins, dedicated to uncovering the truth behind the recent disappearances of prominent scientists, stumbles upon a clue pointing to Dr. Totenkopf, a mysterious scientist. Polly collaborates with her former lover and accomplished aviator, Joe “Sky Captain” Sullivan, who pilots his private warplane to defend the city against the robotic invaders. As Polly and Joe navigate the perilous situation, their investigation leads them to understand that the attack is only a fraction of a much larger and more sinister plot threatening the entire world.

Embarking on a dangerous journey, Polly and Joe recruit the aid of Joe's loyal technician Dex and the enigmatic Commander Francesca "Franky" Cook, who commands an all-female squadron of flying aircraft carriers. Their adventure takes them through treacherous Himalayan mountains, into the depths of the ocean, and across lush, uncharted lands. Along their quest, they must grapple with sky pirates, futuristic technology, and their own unresolved romantic tension. As they draw closer to the heart of the mystery, they must confront Totenkopf's diabolical creations, racing against time to prevent his apocalyptic vision from becoming a reality. The duo's bravery and ingenuity are all that stand between mankind and a new dark age.