At its most basic, Avengers: Infinity War is a movie that follows the tyrannical Titan Thanos getting his purple hands on the Infinity Stones so he can activate the Infinity Gauntlet, snap his fingers, and wipe out half the universe's population. But, spoiler alert, the film didn't actually show him obtaining all six Infinity Stones. He already had the Power Stone plugged into his Gauntlet when the movie opened. Infinity War explained Thanos' acquisition of the gem through Thor, who revealed that the mad Titan "decimated" the war-torn planet of Xandar and captured the Power Stone. So why didn't fans get to see Thanos actually do this in the film?