This early, the discussion has already moved from "Avengers: Age of Ultron" to "Avengers: Age of Ultron" which is more than three years away in 2018. Plot speculation and theories have come forth. This is one of the likeliest ones.

Most of the theories only have the basis of the upcoming movies and the fact that there will be two parts of "Avengers: Infinity War." The giveaway is that there will be something unresolved from the first movie, and that is:

Thanos will complete the Infinity Gauntlet in Infinity War Part One -

"Don't expect Thanos to come in to this movie with the Infinity Gauntlet already completed - expect him to come to Earth to find the final Infinity Stone, so that the moment he completes it and becomes all-powerful gets the movie off to an awesome start.

Also, expect that particular final piece in the jigsaw to be the Time Gem - or at least the Marvel Cinematic Universe equivalent - which we believe is on Earth and will be utilised by Captain America in the Age of Ultron movie.

Essentially, you won't see the Infinity Gauntlet with all six Infinity Stones in it until Avengers: Infinity War."

It could actually be at the end of Part One, with the entire movie a race for the final gem (hint: Soul gem). What this means is that they still need a character from the second batch of movies to defeat Thanos. The two movies in between will be "Captain Marvel" and "The Inhumans."

Based on that conclusion, the confirmed Avengers - Guardians of the Galaxy mash up will not be enough.

"We're fully expecting the Guardians of the Galaxy to join the Avengers in the fight against Thanos in this movie - albeit most likely not until part two - but don't for one minute expect the combination to be enough to make the Mad Titan so much as bat an eyelid.

In the comic books, Thanos at his baseline levels is more than enough to stomp both of these teams into oblivion by himself and, wielding the Infinity Gauntlet, they might as well be fleas.

Thanos may well end up being defeated over the course of the two installments, but it certainly won't be in a physical fight. The teams of heroes will have to rely on extenuating circumstances or their wits to defeat him."

"Avengers: Infinity War, Part One" will be released on May 4, 2018 and "Part Two" a year later on May 3, 2019.