Winter Soldier was a 2012-2013 comic book series written by Ed Brubaker (and Jason LaTour), that ran for 19 issues. It features James "Bucky" Barnes as the Winter Soldier, recently returned to the role after spending time as Captain America, and Black Widow.
Former Soviet agent Leo Novokov, one of Bucky's former pupils, kidnaps Black Widow and brainwashes her to assassinate the First Lady. Bucky is able to stop her and break her programming, or so he thinks.
Bucky discovers that Natasha's programming runs far deeper than he thought, and that to save her, he may have to undergo the same brainwashing process himself.