The last time viewers saw Bucky Barnes on the big screen was during one of Captain America: Civil War's post-credits scenes, and he was resigning himself to cryo-freeze yet again after a successful escape from a near-death showdown with Iron Man. "I can't trust my own mind," he explained sadly to an equally battle-weary Captain America, referring to the sequence of activation trigger words Hydra had programmed into him to transform him into a ruthless killing machine.

RELATED: Prelude Comic Explains Every Avenger’s Pre-Infinity War Status

However, Bucky's newly re-frozen status represented some interesting complications for Avengers: Infinity War which, in its first trailer, showcased a very much thawed-out Bucky Barnes fighting right along side Captain America and the Wakandan army.

So, naturally, something had to have happened between the end of Civil War and the start of Infinity War to free Bucky's mind from his Winter Soldier programming -- but the question was, what?

Luckily, Marvel Studios released a prequel comic this week to give some answers. Infinity War: Prelude #1, by Will Corona Pilgrim and Tigh Walker, picks right before the conclusion of Civil War's brutal ending battle and continues through the fallout of the following weeks.

Here, we see a genuine reconciliation between T'Challa, Steve and Bucky who had, up to the third act of the movie, been working aggressively against one another -- a moment that we had to assume happened, given the post-credits setting where both Steve and Bucky were in Wakanda -- but were never actually shown in full.

But that's only one piece of the puzzle. The issue goes on to elaborate that Bucky's return to cryostasis is actually at the behest of Shuri, a genius Wakadan scientist and engineer who just so happens to be T'Challa's younger sister.

Shuri explains that the cryo-freeze is necessary for her to make a map of Bucky's mind, which, in theory will enable her to remove the programming manually, similar to stripping out lines of problem code from a computer. There is a catch, however -- she runs the risk of accidentally "rebooting" Bucky's brain entirely, which may or may not strip him of all his memories, not just the ones Hydra implanted and corrupted during his transformation into the Winter Soldier.

That's a challenge, because, as Shuri is quick to point out: Bucky has no shortage of traumatic baggage to sort through, and not all of it has ties back to Hydra.

Still, the path and course of action is clear -- and Shuri was, apparently, successful in her endeavors, given Bucky's very much alive, awake and functional status in the Infinity War trailer... or so we can hope. Give the potential risks and complications, it's unlikely that we've seen the very last of Shuri and Bucky's story in Marvel's Infinity War build up.

RELATED: Infinity War: Every MCU ‘Win’ That Left Earth Open for Thanos’ Attack

The second and final Infinity War: Prelude comic is set to hit shelves on Feb. 28, and, with any luck, is primed to bring us the rest of the story -- and maybe even a real origin story for the new metal arm Bucky was seen sporting in the trailer.

Avengers: Infinity War opens on May 4 in theaters nationwide.