On the third go-round for the “Night at the Museum” franchise, it’s getting harder to blow the dust off the come-to-life relics, charming though they may be. Ben Stiller and crew go for the easy laughs, spackling the cracks in their armor with a cavalcade of marquee-name cameos and one dizzying action scene after another.

As Larry, night guard at the Museum of Natural History who moonlights as impresario of statues come to life, Stiller has a hefty new challenge on his hands: A quest to keep a sacred tablet from crumbling, and with it all of Larry’s animated charges, necessitates a trip to the British Museum in London with his posse.

That includes Egyptian prince Akhmenrah (Rami Malek), Dexter the crazy capuchin monkey, Larry’s Neanderthal doppelganger (also played by Stiller, the better to show off his chiseled biceps and triceps), thimble-sized cowpoke Jedediah (Owen Wilson), Attila the Hun (Patrick Gallagher) and Teddy Roosevelt (a relatively low-key Robin Williams). While you get the feeling that Williams was just going through the motions, his every moment onscreen is bittersweet to watch.

An unnecessary annoyance: This adventure is a total bro party. The only female character among the rescue squad, Sacajawea (Mizuo Peck), is figuratively as well as literally a wax figurine whose few lines are superfluous and forgettable. Which makes bubbleheaded, irrepressible London guard Tilly (Rebel Wilson of “Pitch Perfect” fame) a godsend during the few scenes she shamelessly chews up. This movie could have used less Owen Wilson, more Rebel Wilson.

Between her, dry quipster Steve Coogan as Octavius and former “Downton Abbey” milquetoast Dan Stevens as the impossibly handsome, peevishly noble and rather dim Sir Lancelot, the non-Yanks trounce the Americans in the funny department. (Ricky Gervais in his throwaway role as museum director Dr. McPhee doesn’t count.)

Simply tossing lots of frantic action scenes and celebrity artifact drive-bys into the sarcophagus — like a fancy-footed Dick Van Dyke, the late Mickey Rooney and Ben Kingsley — can’t hide the antiquated feel of a once-original concept. That said, this threequel is the type of harmless escape fare that holiday-movie crowds go for in droves.