The Avengers will surely rank among the best superhero movies, if not summer blockbusters, of all time. Unlike some recent franchises, this one offers comprehensible action sequences, good laughs that don't rely on crude humor, and a treatment that's true to the beloved source material.
While big on Marvel mythology and action, it's relatively short on complexity. The headquarters of SHIELD—the U.S. government's high-tech law enforcement division—is infiltrated by Loki (Tom Hiddleston), the evil Norse god of mischief and half-brother to Thor, god of thunder. Brainwashing some agents and scientists to assist him, Loki steals the Tesseract, a glowing cube of unlimited energy and ultimate power. Worse, he has made a pact with an alien race to open a portal with the Tesseract and enslave humankind.
On the brink of war, SHIELD director Nick Fury (Samuel L. Jackson) enacts a desperate plan: to call upon Earth's mightiest heroes to battle its mightiest villains. Iron Man (Robert Downey Jr.), Captain America (Chris Evans), Thor (Chris Hemsworth), and the Hulk (Mark Ruffalo)—perhaps you've heard of them? Along with SHIELD agents Hawkeye (Jeremy Renner) and Black Widow (Scarlett Johansson), they're humanity's last hope.
In short, it's your basic superheroes-saving-the-planet story. But getting there is the challenge. These characters are used to playing solo. Egos clash. Each has personal baggage. Stan Lee's Marvel characters have endured because they're ordinary people with extraordinary powers—larger than life superheroes still grounded by their humanity, wrestling with everyday flaws and emotions.
Director and co-writer Joss Whedon (Serenity, TV's Buffy the Vampire Slayer) shares this trait in his work. He understands characters are key, so much of this film is spent on the heroes getting to know each other and understanding their roles. This leads to some tension, arguing, fighting, and it's a blast to see Iron Man go toe-to-toe with Thor, escalating their battle until clearer heads prevail.
A film like this shouldn't work, because when characters battle for screen time, more typically yields less. But that actually plays to the plot, allowing the personalities to play off each other, ultimately making the cast stronger; we're never bored watching any single character.
It also helps that The Avengers isn't saddled with origin stories. We already know who these characters are, freeing them up to explore new directions. It makes for a rare movie that is greater than the sum of its parts.
The biggest surprise is the level of wit and humor—but that's typical Whedon. As Tony Stark/Iron Man, Downey gets his usual quips, but he doesn't run away with the film. Thor and Captain America have some good bits, and the introduction to Black Widow in the middle of a Russian espionage mission is pure Whedon in twists and timing. But Hulk steals the show a few times, causing audiences to cheer—and Marvel to sign a long-term picture deal with Ruffalo.