You don’t need the mind-enhancing powers of Indiana Jones and the Kingdom of the Crystal Skull’s titular MacGuffin to guess that in the fourth installment of the franchise, our man in the fedora is going to have to take some punches. And not just the nose-busting kind—more like gags about retirement homes and pruned geezers shaking their canes at good-for-nothin’ punks before falling into a deep and sudden sleep.

“You know, for an old man, you ain’t bad in a fight,” one particular good-for-nothin’ punk says to the iconic archaeologist. “What are you, like, 80?”

Henry Jones Jr. is hardly ready to start spending his afternoons feeding ducks. But when word leaked of a third sequel, to be released 19 years after the character literally rode off into the sunset in Indiana Jones and the Last Crusade—and with star Harrison Ford now a Medicare-friendly 65—both the actor and series creators Steven Spielberg and George Lucas had to realize that even adventure-hungry devotees were snickering about the prospect of a decrepit action hero. So in a best-offense-is-a-good-defense move, the filmmakers (including scripter David Koepp, mercifully fleshing out Lucas’ story idea lest some policy-droning spacemen show up) decided to throw a few he-ain’t-what-he-used-to-be jabs at themselves first.

Those jokes stop before they get old; the same can’t be said about the cutesy gopher reaction shots that front-load the film—which, when combined with a ’50s rock ’n’ roll soundtrack instead of John Williams’ famed theme makes the new project feel like a Caddyshack prequel. And speaking of spacemen: Well, there’s no intergalactic politicking here, but the plot does involve aliens. Why did it have to be aliens?

Ford’s age, an uneven tone, an occasionally ludicrous hunt for a crystal skull that may have some fans scratching their bony skulls—none of these eyebrow-raisers are enough to keep the newest Indy from being a decent popcorn-muncher. It kicks off in 1957 in Nevada, with Dr. Jones betrayed by partner Mac McHale (Ray Winstone, who. was. Beowulf! but is utterly ­personality-free here) and cornered by the KGB. Their leader is Irina Spalko (Cate Blanchett, also dull beyond her severe hair and cheekbones), and she wants Jones to help her locate a gewgaw that will boost her telepathy and therefore enable her to take over the world, or some such.

Jones escapes her, in a creepy-cool sequence that echoes Spielberg’s obsession with suburbia as he stumbles into a mannequin-occupied, Howdy Doody-tuned home of a nuclear-testing site and, uh, survives an atomic blast. (This, astonishingly, isn’t the film’s most unrealistic stunt.) But Jones and Spalko will meet again when the professor is approached by a kid named Mutt (Shia LaBeouf), a greaser dropout whose mom is missing and was told Indy is the one man who can save her. A couple of chase scenes later, Mutt is officially Jones’ sidekick, and they’re off to South America to hunt for…stuff. (There’s a lot of monotonous, none-too-slick exposition here if you care to listen hard.)

Like its predecessors, Kingdom of the Crystal Skull is dominated by two milieus: dust bowl and rain forest. The adventure-serial animated maps, complete with a plane and red line to show the audience where our heroes are traveling, are back, and Spielberg’s use of film and minimal CGI mostly keeps things looking old-school. (Still, longtime Spielberg collaborator but first-time Indy cinematographer Janusz Kaminski can’t help but give the film his trademark polish; dirt roads have never been so beatifically lit.)

Even if the supporting characters are flat, Koepp, who last scripted 2005’s excellent Zathura: A Space Adventure, gives the script a lighter touch than previous installments, with Indy being simultaneously grumpier and more charming. Jones’ reunion with Marion Ravenwood (Karen Allen, looking her age compared with her more steadily working and worked-on peers) lends a spark, though their relationship, like the others here, is about as thin as the pages of Indy’s tattered book of clues.

But really, the Indiana Jones series was always about the adventure, not the people, and in that regard the important boxes have all been ticked off: There are skin-crawling critters, spooky catacombs, sword fights between enemies straddling speeding jeeps. More important, Ford doesn’t look ridiculous. Turns out this old man can still take hits to both body and ego and remain as cheer-worthy as the first time he rocked a bullwhip and dusty lid.