Let me just get this out of the way first. While it hasn't been confirmed, a good reason why Marvel Comics put their name on "The Avengers" was to avoid confusion with an ill-received feature film based on the other Avengers, which came out a few years ago. Some people are anal like that.
Enough digression. Let me just summarize "Marvel's The Avengers" for you.
It starts with Loki, the adopted (so he says) half-brother of Thor. Loki (Tom Hiddleston) has been tasked to locate the Tessaract, which comics fans know better by the more common appellation of the Cosmic Cube. Now, who would hire on Loki to be a courier? Ah, that would be telling, and while most online fanboy critics have already spoiled it, I ain't one of them. Anyway, in the course of hijacking the Cube from S.H.I.E.L.D., Loki subjugates agent Clint Barton (Jeremy Renner) and a scientist friend of Thor's to do his bidding. Considering that Barton's backstory for this movie has him as an assassin instead of a carnival archer, this fits.
Confounded and concerned, Nick Fury (Samuel L. Jackson) begins assembling the troops, starting with the sexy superspy, Natasha Romanoff, aka the Black Widow (Scarlett Johanssen), who is herself being interrogated by some enemy agents. Handcuffed to a chair, the Widow still manages to beat the crap out of these guys and make good her escape. Steve Rogers (Chris Evans) is busy pounding away on a heavy bag when Fury comes a'callin'. The Widow locates Dr. Bruce Banner (Mark Ruffalo) in another country. Agent Phil Coulson meets with Tony Stark (Robert Downey, Jr.), and one surprise is the seeming friendship between Coulson and Stark's secretary-girlfriend, Pepper Potts (Gwyneth Paltrow). Tasty. As Captain America, Rogers locates Loki in Germany and engages him in battle.
Surprisingly, Loki is captured, but that's when the fun really begins, especially after Thor (Chris Hemsworth, "The Cabin in the Woods") takes him out of S.H.I.E.L.D. custody to exact his own vengeance. That leads to the predictable battle royale with Cap & Iron Man. In due course, with Loki back in custody, the seeds of discord are planted among the heroes. Inevitably, Banner morphs into the Hulk and there is something that was left over from ol' Greenskin's last film brought to bear.
The Cube is being used to create a portal that will bring an alien armada to our world. Barton is finally freed from Loki's control by the Widow, and there are hints of the romance that they had shared in the comics way back when. You really need to see what happens when Loki tries to reason with Hulk. In a word, hilarious.
Suffice to say, the invasion is thwarted, Loki, Thor, & the Cube head back to Asgard, and everyone else settles back into their own lives. Well, almost everyone. One casualty to speak of. I won't say who.
Seems to me that writer-director Joss Whedon, the genius who gave us Buffy, the Vampire Slayer 20 years ago, thought one hot agent in a black jumpsuit wasn't enough. It's uniformly necessary for S.H.I.E.L.D. agents, particularly Maria Hill (Cobie Smoulders, How I Met Your Mother), cast here as Fury's second in command. The closing credits give us a clue as to what to expect in the eventual sequel, which won't be ready for at least another 3 years. "Iron Man 3" is on the docket for next year.
Clocking in at a shade over 2 hours, "Avengers" works, but drags in spots. All the predictable Marvel touches are there, including the inevitable cameo by Stan Lee.
Among the trailers:
"Battleship" (next weekend). Ugg.
"Dark Knight Rises" (July 20). I don't like Bane's outfit, particularly the mask, but it looks like they hit the jackpot with Catwoman.
"Amazing Spider-Man" (July 6). The wild card may actually be Denis Leary (ex-Rescue Me) as Capt. Stacy, more so than the use of the Lizard.
"Brave" (coming out next month, I believe). A female Robin Hood? Sort of, but not quite.
"End of Watch" (September). Reminds me of "Colors" a generation ago, but with a different vibe.
"Frankenweenie" (October). Tim Burton returns to Disney. That's usually a winning combination.
Speaking of trailers, here's one for "Avengers", compliments of Marvel's YouTube channel: