Now that the Avengers are finally back in movie theaters where they belong, we are officially all Ultron'd out. Sorry, robot James Spader, but you are old and busted. The new hotness is Thanos and his quest to collect all the Infinity Stones, as Thor told us during "Avengers: Age of Ultron."

But wait a minute... what are Infinity Stones? Sure Thor said they're important, but he did a real bad job of explaining why exactly we should be worried about them -- basically he just flew off back to Asgard like:

If you're looking for a more thorough explanation than the "HEY VISION'S COOL GUYS DON'T WORRY ABOUT IT," then don't worry, we've got the hook up for you.

The Infinity Stones

In case you forgot that part of "Guardians of the Galaxy" where Benecio del Toro first took us on an Infinity stone exposition journey, here's a refresher: back in the Before Times when the Universe didn't even exist yet, a group of cosmic entities took six ancient powers (what the Collector calls "singularities") and molded them into "concentrated ingots" for easy use. Now they're scattered all about the universe and can only be wielded by "beings of extraordinary strength."

Tessarect

The Tessarect is the first cosmic power we ever encountered back in "Captain America: The First Avenger." It contains the Space Stone, which allows the user to cross vast distances of space through wormholes. The Asgardians kept it locked in Odin's vault for a time until the Allfather dropped it on medieval Earth, where it was sealed away with some viking bones for hundreds of years until HYDRA got its hands on it. Then SHIELD hung onto the cube for a while, and after the catastrophic events of "The Avengers," it got shipped back to Odin.

The Orb

The first movie to namedrop the Infinity Stones, "Guardians of the Galaxy," introduced us to the Power Stone, which can be used to decimate every living thing in a wide radius. No idea why it was just hanging out in a ruin for a while until Peter Quill snatched it, but Ronan the Accuser also wanted it so he could destroy all the Xandarians in the universe and then hand it off to Thanos, who's trying to collect all six (more on that later). Right now, it's currently still with the Guardians.

The Sceptre (and also, The Vision)

Much to the amazement of fans whose theories were proven completely right, the Mind Stone is located in Loki’s sceptre, and can bend the will of any living person (except people with nuclear reactors for hearts, of course). It was given to Loki by the Chitauri and got lost on Earth soon after that, during which time HYDRA used it in their human enhancement experiments to create the Scarlet Witch and Quicksilver. Now it's sitting on top of the Vision's forehead (fun fact, in the comics his headpiece is actually called the Solar gem).

Aether

In “Age of Ultron” it’s officially revealed that the Aether, an ancient power guarded by the Asgardians until “Thor 2: The Dark World” took place, is also a stone. But which one? Our best bet is the Reality Stone, given its ability to grant its user unlimited abilities.

Time Stone

In the comics, the Time Stone does exactly what you'd expect -- it gives the user the power to time travel, look into the future, and even trap enemies or entire worlds in time loops. Can you even THINK of the possibilites that time travel could bring to the MCU? You think Steve Roger's sad Peggy dream in "Age of Ultron" was bad enough, just wait until he's tempted with the thought of going back to the past for good.

Soul Stone

This nifty little gem grants its user the power to basically do anything they want to another living being's soul. You can look in it, heal it, trap it in a self contained world, or even steal it (which is the soul gem's favorite thing, as it really likes collecting souls -- did I mention it's also sentient?).

In the comics, the time gem is orange and the soul gem is green (well, USUALLY -- they change around a lot), but given how they've been switching up all the colors on us so far in the MCU, it's hard to tell which will be which.

The Gauntlet

All gems need a setting, and the one that Thanos has planned is pretty neat. Eagle-eyed Marvel fans will note that something veeeery similar to the Gauntlet appeared as an Easter Egg in "Thor: The Dark World." So does that mean Thanos has broken into Asgard?

Nope, says Kevin Feige -- there's actually a much different explanation. " I won’t tell you too much but he is not grabbing it from Odin’s Vault," he said to /Film earlier this week. "That is not [Odin’s Vault]."

Thanos

So why is the Mad Titan collecting all of these stones? In addition to just wanting all the phenomenal cosmic power, the comic book version of Thanos has a very specific ulterior motive in mind: to wipe out sentient life in the universe as a way to court Death. Not the abstract concept, mind you -- he is literally in love with the female personification of Death. Spoiler alert! It does not really work out for him all that well, because giving Death MORE death as a present is kind of like giving Taylor Swift a bunch of guitars and cats. She's got that covered, dude.

Also, fun fact: some SUPER ingenious Marvel nerds have noticed that if you take the first letter of every -- T for Tessarect, A for Aether, O for Orb, S for Scepter -- it starts to spell out the name "Thanos." Which means that we're looking for an H and an N now, right?

When Will We See The Last Two Stones?

Now that "Age of Ultron" is over and "Infinity War" lurks just beyond the horizon, where do we look for the next Infinity Stone? "Ant-Man" seems like more of a smaller, Earth-based heist film, so probably nothing there; "Civil War" is already stuffed to the gills with heroes, AND Cap has encountered several stones already in both his first movie and the two "Avengers" sequels, so probably not there either.

But! Thanos's evil plan won't come to roost until May 2018, and in the meantime I bet that "Doctor Strange" will probably get his hands on a stone during his debut film next year. Given that he currently possesses the Soul Gem in the comics, I'm guessing that's the one he'll get saddled with -- and it would be a great way to explain his mystical, mysterious powers.

As for the Time Stone? Sure, Cap would be the easiest choice for that, but I'd love to see it appear in the "Captain Marvel" film instead, which will drop between both "Infinity War" parts. There's definitely comic book precedent: the recent Kelly Sue DeConnick-penned run involved Captain Marvel getting stranded in the past and meeting up with an all-female team of World War II fighters, the Banshee Squadron. There'd be plenty of room for an Agent Carter cameo in there, too!

Now where do I find a reality stone to make this happen?