Stark returned home to find his inventions stolen, notably a document on Nitramene, one of Stark's dangerous formulas. America deemed Stark a traitor despite him appearing in front of Congress led by Senator Webster. Seeing that he can't convince the government, Stark decided to leave the states to Europe before informing Peggy Carter to find his inventions with the assist of his butler, Edwin Jarvis. The Strategic Scientific Reserve had Stark on their most wanted list since he didn't appear to the hearings, and was deemed a traitorous fugitive.
After Brannis betrayed Leviathan and became a "independent businessman", he have Nitramene created as an explosive bomb, and sell them to the black market. One of his many buyers was Spider Raymond, a criminal who owned a night club called La Martinique. Carter learned of the deal, and disguised herself at the club to sneak into Raymond's office to find what he had bought from Brannis. Carter found a bombed version of the Nitramene, and left the club to her apartment, where she disarmed in the bathroom. Returning from there, she was attacked by Leviathan agent Sasha Demidov, but defeated him before going to Jarvis for assistance.
Brannis then went to another buyer, Miles Van Ert, an employee of the Roxxon Corporation. At the Roxxon Refinery, Brannis was ready to make the deal with more Nitramene bombs, but was prevented by Agent Carter, who threatened the operative. Brannis primed one of the bombs, and warned her that Leviathan was coming before leaving on the Daisy Clover. Carter escaped with Jarvis in his car from the explosion, turning the refinery into rubble. Carter would later investigate the driver of the truck, and was successful in incapacitating Ert and finding the name and address of Sheldon McFee. While Brannis was getting buyers, Demidov was killing fences and dealers before getting information on the former's whereabouts.
In New Jersey, Peggy Carter and Edwin Jarvis went to Sheldon McFee's home and found the Daisy Clover milk truck. Inside, Carter found countless amounts of Nitramene, confirming her theory that it was the same one that Brannis escaped the night she confronted him at the refinery. Carter entered the home to find McFee watching The Captain America Adventure Program, and the two fought until she knocked him unconscious. She tied him to a chair, and noticed Brannis attempting to escape in the milk truck, but it was disabled by Jarvis. Carter held Brannis at gunpoint, who asked for protection from Semidov, who was known as "The Man in the Green Suit", and was forced to drive to Manhattan.
As the trio were driving there, Semidov leaped on top of the truck, and shot Brannis in the shoulder. Carter engaged in combat against Semidov on top of the vehicle, and eventually defeated the assassin, making his hand be stuck to the truck. The trio jumped out of the truck as Semidov and the Nitramene went into ocean, exploding and killing the assassin. Dying from his wound, Brannis drew a picture of where Stark's secret technology was hidden, as the pair left when sirens were approaching.
Peggy Carter and Edwin Jarvis found Howard Stark's weapons inside The Heartbreak, where the former was attacked by Jerome Zandow. Carter and Jarvis were able to defeat him by using the constrictor, and left the ship before the SSR could arrive. Sheldon McFee would be found tied to his chair by Jack Thompson and Roger Dooley, who were informed that it was a woman who had done this, and found evidence at Brannis' death spot. Zandow would be arrested and was to be driven to the New York Bell Company Office by Ray Krzeminski, but both were killed Leviathan agent Dottie Underwood. Howard Stark returned to America by paying Otto Mink, and was reunited with Carter and Jarvis before going into hiding at the Griffith Hotel.