It’s a pity that “Jack Reacher: Never Go Back” fails to support Cruise and his co-stars, all of whom are acting as if their lives depended on it. There’s a great movie buried somewhere in here—a strange but beguiling family comedy and a meditation on nature vs. nurture, with a bit of shooting and punching thrown in—but the filmmakers never figure out how to excavate it. There’s a touch of 1980s Hong Kong action cinema in the way that director Edward Zwick and his co-writer Marshall Herskovitz (rewriting Richard Wenk’s script) juxtapose bone-breaking fisticuffs with deadpan-goofy scenes where Jack and Susan—who’s basically a female Jack, with the same anger-flexing jawline—struggle to protect and half-assedly parent Samantha as the trio runs from city to city, fending off assassins and trying to clear Susan’s name. But Zwick doesn’t have the Hong Kong wildness required to pull off that kind of film. He’s an intelligent director, but too earnest and careful for material like this.

There are a handful of genuinely funny moments in which Jack, Susan and Samantha—a street-tough kid whose mom was a prostitute and drug addict—fall into the familiar “Father Knows Best” patterns even though they’re holed up in a New Orleans hotel while trying to get to the bottom of an Afghanistan-based arms smuggling operation run by a Halliburton-type military contractor. None of them have experience behaving within a traditional mother-father-child configuration, so they’re a bit like actors who’ve been thrown into a play without benefit of having read the script and are forced to improvise, badly. Susan and Samantha’s version of mother-daughter bonding includes a tutorial on how to wrench a gun from a man’s hands and kick him in the testicles. When Samantha sneaks out without permission one night, Jack and Susan confront her when she returns, and Jack half-sputters, “Where were you?”

The sight of two skull-cracking soldiers failing to control a teenage girl is a good joke, and remarkably, it never gets old. Unfortunately, it never becomes something other than a joke, or an undeveloped notion. The movie is filled with undeveloped notions, as well as scenes that might’ve been dazzling, or at least clever, if Zwick and Herskovitz had been able to settle on a tone and a vision and develop them. Instead they march along with mild enthusiasm but no gusto, alternating dry-but-not-dry-enough comedy with action scenes that are competently executed but nowhere near as inventive and stirringly perverse as the best stuff in the original “Jack Reacher,” a likewise pretty-good military conspiracy thriller enlivened by Cruise’s junkyard dog sourness, a campy villain performance by Werner Herzog (who has no equivalent here, alas), and a couple of brilliantly staged, close-quarters fights.