Captain America: Civil War - 10 Biggest Things We Still Don't Know

5. Did Bucky Kill Howard Stark?

It's been long-rumoured that Bucky, or rather The Winter Soldier, may have been behind the deaths of Iron Man's parents, Howard and Maria Stark, especially after Arnim Zola revealed to Cap in The Winter Soldier that HYDRA staged their deaths to look like a car accident. Could one of the focal subplots that drives the Civil War forward be that Tony finds out that Bucky killed his parents? The Likely Answer: This one seems too perfect not to be true. Also consider the brief sequence in the final trailer where a glassy-eyed Tony hits Cap in the face: could it be that Stark just found out the truth, hence his rather out-of-character sucker punch to Cap's face? It would certainly help enhance the ambiguity of the central scenario and balance things more in Iron Man's favour (considering how easy it would be for Cap's side to be the "right" one).