1 part Ongoing Andrew Walker, a brilliant inventor, stands in his lab, determined to stop The Viper, a Hydra agent with a time device. Ignoring his mentor Professor Levitt Oswalt's advice to rest, Andrew suits up in his advanced Rocket suit and travels back to World War II to prevent The Viper from altering history. In the chaos of battle, Andrew encounters a young Steve Rogers, who hasn't yet become Captain America. Together, they save a wounded soldier and form an alliance to stop The Viper.
The Viper ambushes them, leading to an intense battle. Despite their efforts, The Viper escapes using his time device, leaving behind a tracking device that leads Andrew and Steve to Cold War Berlin. There, they face new challenges, including an encounter with TVA agents who initially see them as timeline disruptors but eventually agree to help.
Andrew and Steve track The Viper to a hospital where Andrew's mother is about to give birth to him. The Viper's plan is to kill Andrew's mother, ensuring Andrew never becomes Rocket-Man. A fierce battle ensues in the hospital, with Andrew and Steve fighting valiantly to protect Andrew's family. The TVA agents assist, and they manage to subdue The Viper, who is then taken into TVA custody.
Andrew returns to the present, visiting his parents' graves and vowing to honor their legacy by continuing to fight for justice. Meanwhile, The Viper, now in TVA custody, is approached by Miss Minutes with an offer to work together, hinting at future conflicts. As Andrew prepares for new threats, including the looming presence of Dr. Doom, he embraces his role as Rocket-Man, ready to defend the multiverse.