Just a year ago, "The Avengers" filled theaters with the greatest team of superheroes ever assembled. It was a big, expensive spectacle - the culmination of five movies and a decade of development.

"Iron Man 3" kicks off Marvel's "Phase Two" (leading into "The Avengers 2" in 2015) with a rigorous character dissection of Tony Stark, the cocky, billionaire genius who joined a super soldier, the God of Thunder and a raging green Hulk to save the world from alien invasion.

It's a smaller, talkier movie, at least in its best moments, centered with another brilliantly entertaining performance by Robert Downey Jr. as Stark.

A mere mortal among Gods and monsters, Stark opens the film suffering from panic attacks and nightmares about the events in "The Avengers." He tinkers away in his laboratory, building new armor and weapons, all while ignoring the one person who can cut through his megalomaniacal insecurities - girlfriend Pepper Potts (Gwyneth Paltrow).

A flamboyant new terrorist, The Mandarin, uproots Stark's false sense of security. Attacked in his own home and stripped of his arsenal of crime-fighting toys, Stark runs solo for most of the movie, relying on his wits to connect the dots between The Mandarin and a rival scientist (Guy Pearce) who has developed technology that can repair wounds and regrow limbs - but with dangerous side effects.

"Iron Man 3" has its share of explosions and massive blockbuster-y moments, but the difference is the quieter scenes between set pieces. Co-written and directed by Shane Black, known for his playful noir "Kiss Kiss, Bang Bang" starring Downey, as well as kickstarting the buddy cop action craze of the '80s with "Lethal Weapon," this new "Iron Man" throws a few wrenches into the conventions of superhero storytelling.

For one, Black pairs Stark with a mouthy kid for the movie's Iron Man-free middle act, and the movie mines unexpected laughs and revealing character moments from Downey's interactions with young Ty Simpkins. On paper, it sounds like the worst idea for an "Iron Man" movie, yet Black's ear for dialogue turns it into the most enjoyable stretch of the film.

The movie also makes bold use of Ben Kingsley as The Mandarin, an iconic comic book character given an exciting spin by one of the world's best actors.

And while it takes a while for him to get involved, Don Cheadle has several fun moments alongside Downey as Colonel James Rhodes, also known as the government-funded War Machine, now rebranded as Iron Patriot. Forget the flying suits - Downey and Cheadle have the most fun ribbing each other in scenes that Black could have saved for "Lethal Weapon 5."

Does the plot hold together? Not really, especially as Guy Pearce's science project-gone-wrong steals the focus away from The Mandarin. Still, "Iron Man 3" provides a few incredible action scenes (notably a mid-flight rescue aboard Air Force One), and Stark faces major psychological choices that suggest a bold direction for Marvel's "Phase 2."

Plus there's nothing better than Downey verbally sparring with girlfriends, best friends, villains and, especially, a wise-ass 10-year-old.

Grade: B+

Tyler Wilson can be reached at twilson@cdapress.com.