Today news broke that HYDRA officer Baron von Strucker will be making an appearance in The Avengers: Age of Ultron. This also confirms HYDRA's return to modern day America. Now HitFix goes onto specify what kind of role the Baron will play as well as who works for him:
"In "Age Of Ultron," Baron Von Strucker is the initial threat, the guy they're fighting at the start of the film. He does not have a major ongoing role in the film, but he is responsible for bringing Quicksilver and the Scarlet Witch into contact with the Avengers in the first place, since they start the film working either with or or the Baron. If you look at this like a James Bond movie, Von Strucker's the bad guy they'll take care of in the pre-credits sequence before they move into the main story. Quicksilver and the Scarlet Witch have a complicated journey in this film, and the question of whether they're good or bad is one of the big things driving the movie overall."
The Avengers: Age of Ultron hits May 2015