An early scene in “Night at the Museum: Secret of the Tomb” features an archivist, played by the great Andrea Martin, playing Candy Crush Saga on her computer. Had the camera remained over Martin’s shoulder, watching her continue to do so for 97 minutes, the film would probably have upped its quotient of laughs, suspense, and genuine emotion.
But no, instead we have to follow a plainly bored-looking Ben Stiller to London, ostensibly to fix the magic tablet that makes all the museum exhibits come alive at night, but really to put a button on this shrill kiddie franchise by turning it into a trilogy and suddenly pretending that the prospect of saying farewell to these characters will offer the emotional heft of “Toy Story 3.”
The previous chapter of this saga, at the very least, provided the entertainment factor of Amy Adams playing Amelia Earhart like a screwball comedy ingénue and Hank Azaria channeling Bobby “Boris” Pickett as a devious Egyptian monarch. This time, we’re treated to Rebel Wilson as a family-friendly version of Fat Amy from “Pitch Perfect” and Dan Stevens as Sir Lancelot; the latter’s preening machismo stops being funny after about three minutes and instead leads to sad thoughts about poor Lady Mary being forced to raise a child on her own at Downton Abbey.
There’s the usual chasing and pratfalling and whatnot as Stiller’s museum guard Larry — he also does double duty by playing a Neanderthal, but the less said about that, the better — tries to figure out why the tablet is disintegrating. “Secret of the Tomb” replaces the non-stop frantic action of earlier installments with Larry’s troubles as a divorced dad, what with son Nick (Skyler Gisondo, “The Amazing Spider-Man 2”) wanting to go DJ in Ibiza rather than attend college.
Because when young children go to see a movie about dinosaur skeletons and a capuchin monkey (Crystal, acting circles around Stiller) who come alive at night in a museum, what they really want is to hear a divorced dad nagging his teen son about the value of an education. If the previous “Museum” adventures had laid the groundwork for this sort of emotional subplot, it would be one thing, but to suddenly care about the life choices of a character who’s basically the straight man to a tiny cowboy (Owen Wilson) and a tiny Roman centurion (Steve Coogan) and Teddy Roosevelt (Robin Williams) and Attila the Hun (Patrick Gallagher) feels like a massive miscalculation.
Perhaps director Shawn Levy was still in bourgeois family crisis mode after making the similarly unmoving and unfunny “This Is Where I Leave You,” or perhaps Stiller insisted on a more fleshed-out character before accepting one last paycheck for this series. Either way, it’s hard to get invested in the father-son dynamic here, even it when it represents a diversion from the limp comedy bits and the flatlined suspense.
There are a few scattered moments of enjoyment, whether it’s a topsy-turvy chase scene in an M.C. Escher painting or Ben Kingsley and Anjali Jay as rulers whose Pharaoh privilege blinds them to the fact that the Hebrews didn’t enjoy their bondage. (Kingsley gets more to do in a few quick scenes here than in the entirety of “Exodus: Gods and Kings,” go figure.)
Sadly, “Secret of the Tomb” also offers some of our last big-screen moments with Williams and Mickey Rooney; both receive a tribute in the closing credits. The this-is-where-I-leave-the-museum subplot gains poignancy only by virtue of Williams’ untimely passing this year, but in a movie like this, you have to take the lumps in your throat wherever you can get them.