Except this time, as Night at the Museum - Part Duh begins, Stiller's Larry Daley is no longer employed as a guard. He's a successful entrepreneur, with "Daley Devices" infomercials to prove it. (Hot item: a glow-in-the-dark flashlight.) But money isn't everything, you know, and Larry misses his friends, like the little figurines come-to-life played by Owen Wilson (cowpoke Jedediah) and Steve Coogan (Octavius), and that reanimated statue of Rough Rider Teddy Roosevelt (Robin Williams).
Then comes news that the Museum of Natural History's exhibits are being jazzed-up and interactified, and that Larry's dusty old pals are being shipped to "deep storage" in a subterranean archive at the Smithsonian complex. Also on the move: a megalomaniacal Egyptian pharaoh (Hank Azaria), along with a trio of historic heavies - Al Capone, Ivan the Terrible, and Napoleon (Jon Bernthal, Christopher Guest, and Alain Chabat, respectively). They, too, come alive, plotting to take over the Smithsonian, and then the world.
Or something like that.
And so Larry dashes to D.C., dons a guard's uniform, and starts running hither and yon - from the National Gallery to the Air and Space Museum - encountering such notables as the aforementioned 16th president (awoken from his marble slumber at the Lincoln Memorial) and the jaunty aviatrix Amelia Earhart.
It's a sign of just how lackluster NATM:BOTS (or nat-em-bots, as we like to say) is that the heretofore irrepressibly charming Amy Adams - she's Earhart - displays all the vim and vigor of an animatronic wax figure. Spouting putatively amusing anachronisms and showing lots of "moxie" as she tags alongside Larry, she looks hopelessly lost. As for the "chemistry" between Stiller and Adams (yes, there are intimations of romance) - it's inert.
In a film rife with CG and green screen effects - and NATM:BOTS is full of 'em - it's inevitable that the actors will be caught gazing into some middle-distance as if they're interacting with something that's not really there. That's because all of the dinosaurs, the Easter Island totems, and the giant octopus with its menacing tentacles aren't there - they haven't been digitally inserted yet.
So, yes, it really is pretend, this business. But the problem with NATM:BOTS is that Stiller, Adams, and company seem to be pretending that they're having fun, too.
Contact movie critic Steven Rea at 215-854-5629 or email@example.com. Read his blog, "On Movies Online," at http://go.philly.com/onmovies.