In the 1935 horror sequel, "Bride of Frankenstein," one mad scientist toasts another: "To a new world of gods and monsters!" In the 2015 superhero sequel, "Avengers: Age of Ultron," the gods and monsters wage war as the rest of us, puny humans, run scared.
"I don't want to hear the 'man was not meant to meddle' medley," snarks Tony Stark (Robert Downey Jr.), a.k.a. Iron Man. What he does want is "peace in our time," and he thinks he knows just how to achieve it: by cracking next-level artificial intelligence and imbuing his Iron Legion of peacekeeping robots with a benign mind that will happily put the Avengers out of the world-saving business.
But Stark's mad science -- whipped up in tandem with Dr. Bruce Banner (Mark Ruffalo), a.k.a the Hulk -- goes awry with lightning-quick speed: The resulting intelligence Ultron (James Spader) has its own destructive notions of what it means to save the planet and eliminate the need for Avengers.
That's the core conflict of the densely plotted "Age of Ultron," writer-director Joss Whedon's follow-up to 2012's megahit Marvel Comics superhero team-up "The Avengers." Along with Stark and Banner, the sequel reunites Captain America (Chris Evans), Thor (Chris Hemsworth), Black Widow (Scarlett Johansson), and Hawkeye (Jeremy Renner), as well as a gaggle of other Marvel Cinematic Universe characters. Orphan-twin newbies Quicksilver (Aaron Taylor-Johnson) and Scarlet Witch (Elizabeth Olsen) add to the intrigue, and this time actor Paul Bettany graduates from voice-over talent (supercomputer J.A.R.V.I.S.) to a visible role with a "Watchmen"-esque flair.
Though the film's astonishing breadth precludes any great depth, Whedon does a heckuva juggling act. In part, that means winningly cramming in questions about the superhero-industrial complex and the responsibilities therein at a time when humanity is thinking seriously about the disgusting collateral damage of modern warfare and extinction-level threats to our existence. Scarlet Witch puts it to Stark: "Ultron can't tell the difference between saving the world and destroying it. Where do you think he got that from?"
"Age of Ultron" marginally improves on its predecessor through acts of sheer wit and will on the part of Whedon. Demonstrably more confident this time out, Whedon works miracles by intelligently telling the story he wants to tell while remaining beholden to corporate oversight demanding that he shoehorn in characters and pave off-ramps leading to the next set of Marvel movies. This $280 million film unmistakably poses incredibly challenging logistics, and Whedon tames the beast into something spectacularly epic, if a bit exhausting: bursting with destructive mayhem but grounded by interesting character beats, rife with dark implications but seasoned with good humor (ever wonder what an Avengers cocktail party is like?).
Better than any filmmaker yet, Whedon understands comic-book storytelling, with its pop-operatic grandeur and colorful characters, and the Comic-Con crowd has never been better served (Christopher Nolan's Batman films were superior "crossover" successes, but "Age of Ultron" is pure, uncut comic-book fantasy). If you're allergic to comic-book mythologies, this one won't change your mind, but you don't need to know your Mind Stone from your Space Stone to appreciate this action extravaganza leavened by jokes and unlikely romance.
Rated PG-13 for intense sequences of sci-fi action, violence and destruction, and for some suggestive comments. Two hours, 21 minutes.