Are you ready for some total guesswork?

I’m going to speculate on what we might see next May when “Avengers: Age of Ultron” hits theaters.

I don’t have any inside knowledge (my friend in the movie business doesn’t work on these Marvel movies). I’m speculating based on what I’ve read online recently and on recent re-readings of half-century-old comics that told this story before.

And I’ve already written about Marvel’s long game, the climax – most likely in the third “Avengers” movie – that will pit Marvel Cinematic Universe heroes against Thanos, the god-like destroyer and embracer of death.

Josh Brolin voices Thanos in “Guardians of the Galaxy” and likely in future Marvel movies. From scenes we’ve already seen in the “Thor” sequel and in “Guardians,” we know Thanos is pursuing the Infinity Stones to make his all-powerful weapon, the Infinity Gauntlet. Heck, Brolin took the stage in San Diego wearing a mock-up of an Infinity Gauntlet.

But what happens in the meantime, in “Age of Ultron?”

While the MCU has taken big variations away from the established Marvel comic book shorelines we’ve known for a half-century now, I think “Age of Ultron” will mix elements from a couple of milestone “Avengers” comic books.

We already know Ultron is in the movie, obviously, The murderous robot is invented (in the movies at least) by Tony Stark but, like Skynet, gets his own ideas on how to run the world.

And we know that Vision, a synthetic person created by Ultron to kill the Avengers only to end up joining them, is in “Age of Ultron.” He’s played by Paul Bettany, the voice of Tony Stark butler Jarvis in the “Iron Man” movies and “The Avengers.”

“Age of Ultron” creates Ultron (voiced by James Spader) and sets up the conflict depicted in the original 1960s “Avengers” comics, namely issues 55 through 57, when the Vision is introduced. In the comics, of course, Ultron was created by Hank Pym, played by Michael Douglas in “Ant-Man” but that movie’s not coming out until later in 2015.

So Ultron on a collision course with the Avengers, with Vision changing sides. Check.

But who else changes sides?

For this, we go back a few years in the “Avengers” comics, to issue 16, in which the Avengers experiences the biggest line-up change in its young history.

Although Hulk had come and gone and Cap joined the team in “Avengers” 4, the big change didn’t come until issue 16, when Thor flies off to deal with Asgardian issues, Giant-Man (the former Ant-Man) and Wasp decide to leave and Tony Stark decides to retire his “bodyguard,” Iron Man, from the roster.

Who joins?

Three former criminals/crooks/super villains: Hawkeye, the archer (already on the team in the MCU), Quicksilver and Scarlet Witch (who we know are in “Age of Ultron).

While I’d LOVE to see the “Ultron” footage screened at Comic Con, I’m pretty sure the final scene shown – the Avengers lying defeated at Ultron’s hands, Cap’s shield broken – isn’t the end of the movie. Despite the fact I believe it will end up being “The Empire Strikes Back” of the “Avengers” series, “Ultron” won’t end that way. That’s a vision (pun intended) or dream of something plaguing Tony.

No, I think “Ultron” will end with something more dire: The team breaking up. The powerhouses will be gone and Cap will carry on, as he did in the comics, with less powerful teammates like Quicksilver, Scarlet Witch and Vision.

Which will make it all the more essential that big guns like Thor and Hulk return in 2018, the likely release date of the third “Avengers” movie.