Spoilers ahead. What happens to you after you die? Some believe in a heaven and hell, others believe you just disappear into nothingness. Avengers: Infinity War hints that we could be seeing Marvel Cinematic Universe's own take on the afterlife soon, with an ending that left audiences wondering, where did the Avengers go after Thanos dissolved them into dust? Assuming Bucky and Falcon and Black Panther won't be showing up on The Good Place Season 3, the answer probably has something to do with the Infinity Stones and their mysterious power — in other words, the Avengers could be in the Soul Stone.
Infinity War ended with Thanos getting his hands on all six Infinity Stones, snapping his fingers, and causing half the population of universe to disappear into dust. It would be easy to say that the Avengers, and the millions of innocent people who dissolved in front of Cap's baby blues, died, but it's pretty obvious to fans that those who were snapped out of existence aren't really dead — at least not permanently. Assuming they are not dead, the Avengers who were taken by Thanos — Spider-Man, Black Panther, Star-Lord, Mantis, Drax, Groot, Falcon, Scarlet Witch, Doctor Strange, etc — have to be somewhere. Their bodies may have turned to dust, but their souls, the essence of their existence, they must still be alive. The question is: where are they?
It's likely that the Avengers are currently trapped in the Soul Stone. Arguably the most mysterious of the Infinity Stones (at least in the MCU), the Soul Stone has capabilities audiences simply don't know about yet. And one of these is the ability to take souls and, essentially, trap them in a pocket dimension. As reported by Digital Spy, the Soul Stone can be used to transport and manipulate souls, so it's extremely likely that all of the people who turned into dust at the end of Infinity War are now in the Soul Stone's pocket dimension, known in the MCU as the Soulworld.
If the Avengers are stuck in the Soulworld, this could cause a few problems in Avengers 4. As described on the Marvel website, the Soulworld is a peaceful place, a sort of utopia for souls who end up there. On the one hand, this means that the Avengers aren't in pain. On the other hand, it could make it more difficult for them to find their way home. In the comics, the owner of the Soul Stone can control the souls stuck inside it, but it's also possible that the Avengers in the Soulworld will have to play a role in their escape, which means they have to want to leave the peaceful afterlife.
It's worth noting that, as reported by CBR, it looks like Thanos himself is in the Soulworld at the end of Infinity War. Does that mean that he and the Avengers will cross paths? It's possible. Or perhaps, as the wielder of all Infinity Stones, including the Reality Stone, Thanos was able to create his own small pocket dimension separate from the Soulworld.
The intricacies of the Soul Stone and the Soulworld remain unclear, even for fans of the comics. The MCU doesn't always follow the comic books, so it can really do anything with the Soul Stone in Avengers 4, which means it could create another way into the Soulworld to rescue the Avengers. Before Avengers 4 is released in 2019, Ant-Man and the Wasp is rumored to open the door in the MCU for more of the multi-verse, namely the Quantum Realm. It's possible that whatever they discover about the Quantum Realm relates to the Soulworld. Or, maybe it will have absolutely nothing to do with it. Either way, fans are going to have to wait an entire year before they find out where the Avengers went after Infinity War. The most we can do now is sit back, relax, and trade theories.