One of the biggest mysteries going into Avengers: Infinity War was the location of the Soul Stone, the final orange piece of the multi-colored puzzle Thanos needs to carry out his grand mission. As fans predicted, the Soul Stone was introduced in Infinity War in a big way, essentially functioning as the film’s central plot for two-thirds of the movie. But the exact circumstances of its discovery might be a little confusing.

It’s not because the Soul Stone’s location is steeped in impenetrable comic book lore, or because you need to have seen the last 18 movies (!!!) that makes the Soul Stone’s discovery hard to understand. In fact, it’s the opposite. The revelation of the Soul Stone sort of comes out of nowhere, out of the fact that Thanos’s adopted daughter Gamora (Zoe Saldana) knew the location of the stone this whole time. And for her sake and everyone else’s, she refused to share this important information with the class, the Guardians of the Galaxy.

Spoilers for Avengers: Infinity War ahead.

As revealed in Infinity War, Gamora has known the Soul Stone’s location for a very long time. Years ago, long before 2014’s Guardians of the Galaxy takes place, Thanos sent her on a mission to find the Soul Stone and report back. Thanos trained Gamora better than he thought, because Gamora did indeed discover the stone, but lied to dear old daddy so he’d never complete his awful mission of universal genocide.

Avengers Infinity War Nebula
An unseen conversation between sisters Gamora (Saldana) and Nebula (Gillan) reveal that Gamora has known the Soul Stone's location this entire time.

But now, Thanos has captured Gamora’s sister Nebula (Karen Gillan) and hacks into her memory to unearth recorded footage of a conversation between Gamora and Nebula that MCU fans have never seen before. No, it did not happen in Guardians of the Galaxy or Guardians of the Galaxy, Vol. 2 (2017). What fans see is new, and what they see is Gamora telling Nebula the stone is on Vormir, proven by a map that Gamora had burned.

Of course, the hunt for the Soul Stone contained more surprises, mainly the whereabouts of Captain America villain Johann Schmidt, better known as the Red Skull. Schmidt was presumed dead at the end of 2011’s Captain America: The First Avenger, but his time hunting for the stones damned him to a prolonged afterlife on Vormir, doomed to always be close to the Soul Stone but unable to obtain it for himself.

As Schmidt told Thanos, the cost for the Soul Stone is another soul. “A soul for a soul.” And it must be a soul whom you love. So Thanos sacrifices his daughter, whom he legitimately loves in his weird twisted way, and is rewarded with possession of the Soul Stone. From there, getting the Mind Stone (from Vision) and the Time Stone (Doctor Strange) were a cinch. That’s just what happens when you have all the power in the universe.

Avengers: Infinity War is now playing in theaters.