In the 1st season of the series ‘What If…?’ an extraterrestrial being, known as the Watcher, narrates about alternative events taking place in the Multiverse. Peggy Carter receives the Super Soldier Serum and becomes Captain Britain, while Steve Rogers becomes her partner. Due to an unknown virus, the superheroes turn into zombies, countered by Bucky Barnes. Killmonger saves Tony Stark from being attacked in the desert, and Loki becomes the rightful ruler of Asgard. Instead of the Avengers, it is the Guardians of the Galaxy who battle against the Chitauri. Yondu kidnaps T’Challa from Wakanda, who then becomes a cosmic pirate.
In the 2nd season of the series ‘What If…?’, the story of characters from an alternative Marvel cinematic universe continues. The events take place during World War II. Super Soldier Steve Rogers is supposed to participate in an experiment, which didn’t happen due to the interference of a Hydra agent. Steve gets injured, and Peggy Carter is injected with the serum, transforming her into ‘Captain Carter’. As a result, Hydra loses the Tesseract. Rogers receives armor created by Howard Stark, made with the use of the cube.