In Avengers: Infinity War, the ragtag team of superheroes reconvene after the disastrous fallout which occurred in Captain America: Civil War. Only the greatest threat to the universe could bring everyone together like this, and that's what happens when the supervillain named Thanos makes clear his intention to collect the Infinity Stones and destroy everything. In order to fully understand Thanos' mission, though, you need to know exactly how the Infinity Stones work.
You might already understand more about the stones than you think, because they've been sprinkled throughout Marvel movies in the past. In a way, every Marvel film, starting with 2008's Iron Man, has led up to Infinity War, and tons of MCU characters will join together in the new movie to protect the Infinity Stones so Thanos doesn't collect them all. The six stones each represent different aspects of the universe, as Nerdist explains, and included in the collection are the Space Stone, the Mind Stone, the Reality Stone, the Power Stone, the Time Stone, and the Soul Stone. Alone, each stone has immense power; you've already seen a few of the Infinity Stones at work, like in 2012’s Avengers when Loki used the Space Stone to Loki to open a portal allowing the Chitauri forces to invade New York. Together, the stones interact to allow whoever possesses them to have infinite mastery of the universe, according to Screenrant.
Should an evil villain like Thanos collect each of the the Infinity Stones — which appear as oval-shaped gems — he could completely change everything. Even with one or two of the stones, you can do massive damage. According to Nerdist, the Space Stone on its own allows whoever has it to alter the layout and dimensions of space — like what Loki did — but combined with the others, it allows its owner to have omnipresence. The Mind Stone, which lies in Vision's forehead, provides telepathy, but if you combine it with the other stones you can read everyone's mind at once, as Nerdist details. The Reality Stone, meanwhile, allows its owner to change the laws of the world — like turning the color of grass to pink, for example. In Thor: The Dark World, the titular hero gave the Collector the Reality Stone, which comes in a liquid form and is known as Aether.
The remaining stones are The Power Stone, The Time Stone, and The Soul Stone. The Power Stone was first seen in The Guardians of the Galaxy when the Guardians turned it over to Nova Corps. The Power Stone grants its owner incredible strength, according to The Verge. The Time Stone, as you can imagine, allows the person who possesses it to control time, whether that means going backwards or forwards. Doctor Strange holds the Time Stone in the Eye of Agamotto, and Digital Spy suggests it will make Doctor Strange one of the most important characters in Infinity War.
The only stone that the MCU hasn't introduced to its audiences is the Soul Stone — or is it? According to The Wrap, one leading theory about the Soul Stone's location suggests that it lies beneath Wakanda in Black Panther. That could explain why parts of Infinity War will take place in Wakanda.
Each of the Infinity Stones, should Thanos collect them all, will get wielded together by the giant golden glove that you see Thanos wearing in Infinity War's trailers. The glove is known as the Infinity Gauntlet, and Cinema Blend points out that two Infinity Gauntlets actually exist. Apparently, even when dealing with all-powerful magical stones that can alter the universe, the rules that gloves come in pairs still applies. The second Infinity Gauntlet could just come in handy — no pun intended — in Infinity War.
The leading theory about the Infinity Stones' origin states that they are the only remnants from what existed before the universe's creation, according to The Verge. In an interview with Mandatory, Marvel Studios President Kevin Feige reaffirmed this, as he said "They’re all connected." Should Thanos end up collecting those individual entities, the connection they form will likely change the MCU forever.