Avengers: Infinity War is a threequel, but only technically so. This latest big budget team-up from the Marvel Cinematic Universe follows eighteen films that have featured the same incarnations of these characters of comic book lore. The most direct predecessor is not 2015's proper sequel Avengers: Age of Ultron, but 2016's more warmly received Captain America: Civil War, which was an Avengers movie in every way but titling.

Nearly all of the characters who came together in that blockbuster are back, along with the offbeat heroes of the Guardians of the Galaxy films and a couple of principals from Doctor Strange. There's Iron Man (Robert Downey Jr.), Thor (Chris Hemsworth), sporting the short hair and damage of last fall's delightful threequel Ragnarok, Captain America (Chris Evans, now sporting a world-weary beard), Hulk (Mark Ruffalo) or, more often, his mild-mannered alter ego Bruce Banner. It's a lot easier to list the two major characters who aren't present here. Mentioned but not seen are arrow-slinging Hawkeye, whose absence from marketing drove fans to fear a swift death, and Ant-Man, who presumably is occupied by his own quickly approaching sequel.

Everyone else is along for the ride and the lineup that seemed like an abundance of heroes in the record-setting first Avengers back in 2012 seems quaint and restrained in comparison to this epic assembly. Infinity War takes some moments to acquaint characters whose paths haven't before crossed with one another, but it doesn't bother to introduce you to any of them. It rightfully assumes that if you're seeing this, you've probably seen most of the eighteen (seventeen if we eliminate Ant-Man) and know who's who or at least enough to follow along.

Plots are so guarded during development and production phases, but when you think about it, they don't really matter a great deal. I barely remember the specifics of Thor: Ragnarok and Spider-Man: Homecoming, but I remember they were both a blast. Don't ask me to give you a detailed synopsis of Black Panther, but I can tell you I wasn't blown away by that commercial triumph. The plot of Infinity War is almost absurdly simple. A bad lavender-skinned alien named Thanos (motion capture performed by Josh Brolin, but looking a bit more like Bruce Willis) is collecting infinity stones. As tidy exposition explains, there are six different colored stones that have been around forever and control different aspects of existence, like space and time. One of the stones hangs from the neck of Dr. Strange (Benedict Cumberbatch). Another is implanted in the head of Vision (Paul Bettany), one of the characters you might not have noticed if he was missing.

Setting aside their past differences, the Avengers team up to try to stop Thanos from obtaining these half dozen crystals that would give him power beyond anything else in the universe. They're also prominently joined by the Guardians: Star-Lord (Chris Pratt), Gamora (Zoe Saldana), and thick-headed Drax (Dave Bautista). Meanwhile, teenaged Groot (voiced by Vin Diesel) and smartass raccoon-like Rocket (Bradley Cooper) go off with Thor on a separate mission.

Infinity War is directed by Anthony and Joe Russo, the brothers who helmed the overrated second and enjoyable third Captain America movies. Joss Whedon, who single-handledly wrote and directed the first two Avengers movies, has left Team Marvel and was last seen accepting blame for the boring mess that was DC's Justice League. Also coming from the Captain America line are Christopher Markus and Stephen McFeely, the duo who penned all three Captain adventures. The change in personnel gives this a somewhat different feel from the Whedon two, but Marvel is bigger than any creators and we're still very much getting a Marvel movie.

There is a pretty narrow range of quality within the Marvel Cinematic Universe. You've got movies that aren't quite as good as critics claimed (Iron Man, Black Panther, Captain America: Winter Soldier). You've got movies that aren't as bad as their detractors would have you believe (Iron Man 2, Avengers: Age of Ultron). You've got a few genuinely special movies (the first Guardians, the third Thor). And you've got your serviceable origin movies like Ant-Man and Doctor Strange that are fun if a tad forgettable.

There's really no room for Infinity War to surprise. It's too big a movie and too chock-full of characters you already know and like to either disappoint or disarm. It's a Marvel movie and you'd have to have been living in a cave for these past ten years not to know what to expect from those. Infinity War, which was shot back to back with a thus unnamed sequel that will open a year from now, is dark and heavy. It's got a few fun moments: Drax slowly eating nuts and believing he's invisible, Spider-Man again being young and enthusiastic in the throes of combat, Iron Man and Doctor Strange butting their very different goateed heads. But as in The Winter Soldier, the comedy and entertainment take a back seat to action, which in this case is pretty gloomy in an end-of-times kind of way.

Brolin, who bizarrely will be playing another Marvel villain in the imminent Deadpool 2, does a nice job of giving Thanos some weight that digital animators could not. He's at least imposing and given lots of screentime, if not necessarily emerging as a strong character that gives you lots to chew on, which upon reflection has any recent Marvel villain?

Everyone seems excited for this movie and more than they were for Age of Ultron. But there is really no way for the movie to meet those expectations, not with a direct follow-up already in the can and while adding to a tradition that is familiar to all. So, yes, Infinity War is well-made. It's not particularly derivative of all the movies that have come before it. It's an enjoyable ride boasting top-notch visual effects and sound plus all the superheroes you could ever want. But the biggest discussions around it upon release will probably be the same things that has social media abuzz for a while now: who's really going to die and who's only going to seem like they did?