Following World War II, the United States recruited over 1,500 German scientists, engineers, and technicians in the classified "Operation Paperclip". Among those recruited was former HYDRA scientist Arnim Zola, who started working for S.H.I.E.L.D. in an attempt to rebuild HYDRA from inside the newly-founded peacekeeping organization.
In 1991, HYDRA learned that S.H.I.E.L.D. co-founder Howard Stark had recreated the Super Soldier Serum and tasked Vasily Karpov, a sleeper agent embedded in the Russian Armed Forces, with reviving the Winter Soldier. Karpov did as he was told, ordering the master assassin to retrieve the serum and leave no witnesses behind.
On the night of December 16th, Howard and Maria Stark were en route to the Pentagon with the newly-completed serum when the Winter Soldier raced up behind them on a motorcycle and slashed off the front tire with his cybernetic arm, causing it to swerve off the road and crash into a tree.
As the Winter Soldier approached the fallen vehicle, Stark crawled from the car and asked him to help Maria. He recognized the assassin as Bucky Barnes only to be repeatedly punched in the face and have his skull crushed by the Soldier's robotic arm.
After placing Stark's corpse back inside the car and strangling Maria to death, the Soldier proceeded to shoot at a nearby security camera before departing with the serum.
The newspapers the following day reported on the Starks' passing, but their deaths were attributed to a simple car accident. Obadiah Stane assumed the position of interim CEO of Stark Industries as a result.
A Wakandan War Dog stationed in New York investigated the crash site, determining that foul play was involved and even realizing that something had been stolen from Stark. The War Dog informed King T'Chaka of these findings, and offered to look further into the incident.
HYDRA used the Super Soldier Serum to give five individuals the same capabilities as the Winter Soldier, but they proved too dangerous to be sent into the field and remained in suspended animation at a facility in Siberia.
In chronological order:
- Captain America: Civil War (flashback)
- Iron Man (mentioned)
- Iron Man 2 (mentioned)
- Captain America: The Winter Soldier (newspaper)
- Captain America: Civil War (footage)
- Avengers: Infinity War Prelude (footage)
- Captain America: Civil War
- Translates from Russian to: "I have a mission for you. Sanction and extract. No witnesses."
- Captain America: The Winter Soldier
- Iron Man 2: Public Identity
- Iron Man
- The Wakanda Files: A Technological Exploration of the Avengers and Beyond