★ ★

Night at the Museum: Secret of the Tomb, the third film in the family-friendly franchise, brings Ben Stiller back to play the straight man to a bunch of comic geniuses, a capuchin monkey, and an abundance of not-very-special effects.

The premise this time around—not that a compelling setup is really necessary—is that night watchman Larry (Stiller) must travel from New York to London to find out from Merenkahre (Ben Kingsley), an ancient Egyptian on display in the British Museum, why the magical tablet that allows the exhibits to come to life every night is losing its power. Along for the ride are Teddy Roosevelt (Robin Williams), miniature cowboy Jedediah (Owen Wilson) and his Roman figure compadre Octavius (Steve Coogan), Merenkarhe’s son Ahkmenrah (Rami Malek), Larry’s mildly rebellious teen son, and of course, Dexter the mischievous monkey. Once there, they meet up with Larry’s equivalent Tilly (Rebel Wilson), a female night watchman, and Sir Lancelot (Dan Stevens), as well as a number of other museum exhibits who come alive when Larry brings the tablet into the building.

Director Shawn Levy, who also helmed the previous two movies in this series, once again employs a formula that breaks down more or less like this: 40 percent comedy, 40 percent unconvincing CGI, 18 percent warm family sentiment, and two percent monkeys peeing on people. He basically follows the pattern of the other films to the letter, and that lack of inspiration doesn’t help boost a rather dull script by David Guion and Michael Handelman. The endless special-effects sequences quickly grow tiresome, and the theme about fathers learning to let go of sons is ham-fisted and obvious.

However, even though the movie as a whole is nothing more than tired product, there are individual moments that will bring a smile. Levy is comfortable letting funny people linger on a moment, and just about every actor gets a good laugh with some bit of physical or verbal silliness. Chief among them is Ricky Gervais as Larry’s boss in New York. His ability to play sniveling discomfort is peerless, and he does so here with exquisite timing; you wish he could have gone to London, too.

Additionally, in the last 15 minutes, Levy and company take a long time saying goodbye to the series and the characters. While there’s no guarantee that everybody won’t want to collect another easy paycheck in five years, the finale is full of tender moments between Larry and all of the series regulars, and it highlights the best of what these three movies have to offer. The ending will feel even more bittersweet for fans of Robin Williams, whose death earlier this year heightens the poignancy of Larry’s final interactions with Teddy.

Night at the Museum: Secret of the Tomb isn’t the best entry in the series, nor is it a particularly memorable experience. But, if you’ve been onboard since the beginning, it is a better farewell than you get from most film franchises.