Steve Rogers, Bucky Barnes, and Sam Wilson continue the search for Armani - Steve's sister and Bucky's lover - after the events of the previous year, the government takes charge and releases the Sokovia accords, saying the Avengers will no longer be a private organization.
With government forces after her, Steve, Bucky, and Sam find Armani's apartment in Romania, helping her escape and becoming criminals themselves. They are then arrested and taken to a building in Berlin, where their stuff is locked away and Armani is psychologically evaluated by Steve's love interest, who activates the winter soldier, setting her against the whole team, fighting her way out of the building and up to a helicopter where she tries to escape.
The Avengers then fight against each other, Steve, Bucky, and Armani manage to get on the Quinjet and head to Siberia where Armani was kept, finding Steve's love interest there, she shows them a tape from December 16th, 1991, Tony finds out she murdered his parents and he fights against Steve, Bucky, and Armani. T'challa talks to the two women outside the base, having followed the three in the Quinjet. Steve, Bucky, and Armani travel to Wakanda where she gets frozen again in a cryostasis chamber where she will stay until they can get the trigger words out of her head.
Captain Steve Rogers and Lieutenant James 'Bucky' Barnes were best friends, who were given the super soldier serum, are America's best. Steve's sister and Bucky's lover Armani Sasha Rogers joined them to take down HYDRA, the Nazi organization, along with the Howling commandos. Little did they know, Marni would fall from a moving train while trying to capture Dr. Zola, presumed dead for 70 years. After going into the ice to save the world, Steve and Bucky have to wrap their heads around 21st century technology and life.
Brainwashed into becoming a stone cold killer called 'The Winter Soldier' she is tasked to kill Steve, Bucky and Director of SHIELD Nick Fury, as they found out SHIELD had been infiltrated by HYDRA. What will they think when she is tasked to assassinate them? Will she recognise them? With the help of fellow avenger Natasha Romanoff and ex-pararescue Sam Wilson, will the be able to succeed in their mission and restore Marni's memories?