Spoilers for Avengers: Infinity War follow below.
We have known for some time that the plot of Avengers: Infinity War would follow Thanos ( Josh Brolin ) attempting to collect all six Infinity Stones, which would then give him the power to rule the universe - or wipe out half of its population with a snap of his fingers. is the main plot of Infinity War,but the film also explores a little more the Infinity Stones and what they do. There are six in total: the Space Stone, the Spirit Stone, the Reality Stone, the Time Stone, the Power Stone, and the Soul Stone.
It's this last stone that proves to be the most impactful in Infinity War, as Thanos 'journey to find the Soul Stone takes him to Vormir, the planet where the soul stone is hidden. Thanos brings his daughter Gamora ( Zoe Saldana ) with him, and they meet Red Skull who serves as the keeper of the Soul Stone. Red Skull first appeared in Captain America: The First Avenger played by Hugo Weaving , but at the end of that movie the Tesseract (which is powered by the space stone) transported the Red Skull to unknown regions - now revealed to be Vormir. In Infinity War, Red Skull is played by Ross Marquand and iInform Thanos and Gamora that to get the S oul Stone back, you have to sacrifice the soul of someone they love. So Thanos, with tears in his eyes, quickly throws Gamora off the cliff.