The most vital thing that one needs to bring to the movies these days is diminished expectations. This is particularly the case when en route to a highly touted summer blockbuster, or worse, a numbered franchise entry. The feeling of disappointment when a sequel fails to live up to the beloved original film that spawned it is a mute agony all its own. Having suffered through George Lucas’s grotesque, intellectually down-market, and emotionally fraudulent latter-day entries in the “Star Wars” franchise, it was reasonable to assume that Mr. Lucas and Steven Spielberg’s highly hyped new entry in the “Indiana Jones” series, “Indiana Jones and the Kingdom of the Crystal Skull,” would contain something to disappoint everyone.

In the 19 years since “Indiana Jones and the Last Crusade” ostensibly capped the series, star Harrison Ford has become a sexagenarian while Mr. Lucas, who created the Indiana Jones series, torpedoed his own creative credibility with the “Star Wars” reloads. And though still the most gifted film grammarian working at any budget in American cinema, Mr. Spielberg has frequently lent his prodigious directorial savvy to cynically overdeveloped yet ill-conceived script material such as “War of the Worlds” and “The Terminal.”

With that in mind, it’s a pleasure to report that “Indiana Jones and the Kingdom of the Crystal Skull” is not bad. In fact, it’s good. Very good. There’s nothing like a rousing mainstream movie that is actually rousing, and for most of its 120 minutes, “Indy 4,” as it’s been dubbed, is fun, funny, harrowing, and imaginative, and it sustains a relentless pace. Easily the best of the “Indiana Jones” sequels, this latest outing is good enough to revive one’s expectations that summer blockbusters will deliver on any of their ballyhooed promises.

Last week, the popular movie Web site imbd.com quoted “Crystal Skull” producer Frank Marshall’s reaction when Mr. Spielberg expressed frustration at plot leaks that appeared on the Internet prior to the film’s release. The creative team had, after all, sued an extra for breaching a nondisclosure agreement during shooting, and successfully set up a sting to retrieve design sketches and script pages that had been burgled from the film’s production offices. Audiences, Mr. Marshall reportedly reassured the director, are not “coming to see the plot. They’re coming to see Steve Spielberg interpret a story.”

This has turned out to be no boast. From the first shot, “Crystal Skull” plays like a greatest-hits self-tribute to Spielbergian cinematic élan. It’s as if the director went back to the well of his early work in order to refresh his creative juices.

An opening hot-rod race with an Army truck convoy across the New Mexico desert in 1957 recalls the high-octane, pure cinema thrills of Mr. Spielberg’s “Duel” and “Sugarland Express.” Yanked from the trunk of a car belonging to masquerading communist spies, Indiana and his sidekick, Mac (Ray Winstone), exhibit a factitious grace at gunpoint that calls back to the fractious, crisis-driven camaraderie of “Jaws.” A frantic warehouse search led by villainous KGB psychic warrior Irina Spalko (Cate Blanchett) conjures the time-sensitive march to enlightenment undertaken by Fraçcois Truffaut’s scientist team in the first reel of “Close Encounters of the Third Kind.”

While “Crystal Skull” is replete with such de rigueur nostalgic touches as malt shop interiors and Elvis Presley music cues, the post-World War II world that Mr. Spielberg, Mr. Lucas, and co-writers Jeff Nathanson and David Koepp have created is, in fact, a darker place than the one offered in the earlier “Jones” films, which were set in the ’30s and populated by nefarious Nazis. In the new installment, a mushroom cloud and atomic shock wave are more likely to melt eyes and explode heads than the wrath of God. Even though they share the same shelf space, the powerful totem that Spalko and her comrades seek is not the Ark of the Covenant, but a container of remains from a mysterious air crash in nearby Roswell that took place a decade prior.

Having aided the commies at gun point, Dr. Jones is questioned by hostile FBI agents and loses his university teaching position in the ensuing cloud of scandal. Alone, untenured, fearing for the life of his academic colleague Oxley (John Hurt), and tailed by both Khrushchev’s and Hoover’s men, Indiana acquires an unlikely ally in the form of Mutt Williams (Shia LaBeouf), a motorcycle-riding juvenile delinquent.

“You’re like a grave robber or something,” Mutt says in a not-entirely-inaccurate description of the archeologist-adventurer’s job. One of the great pleasures of watching this very amusing, energetic, and borderline inspiring movie is the grace with which it both exhumes and honors the remains of the first “Indiana Jones” film. Filling in a credible backstory connecting on-screen current events to the last of the sequels while dealing with Mr. Ford’s evident aging and the absence of characters formerly played by the now deceased (Denholm Elliott as Marcus Brody), disinterested (Sean Connery as Henry Jones Sr.), or double-booked (John Rhys-Davies as Sallah) actors is no mean feat. But Mr. Spielberg and company meet the task head-on.

Mr. Ford dons the fedora and swings the whip with genuine world-weariness. The addictive mixture of everyman vulnerability and wish-fulfillment heroism that Indiana Jones embodies remains potent, albeit in a more leathery manifestation.

The other manifold pleasures of this film are the surprises, situations, escalations, and marvelously shot and staged action set-pieces that begin to pile up geometrically as Indy and Mutt head to Peru in search of Oxley, and also of Mutt’s mother and Indy’s former flame, Marion Ravenwood (Karen Allen, who flaunts the same grin and sparkling eyes she brought to “Raiders of the Lost Ark”).

Having said this, I will divulge no more, even though, with the film set to open tomorrow, prosecution is unlikely. In truth, after the chaotic, apocalyptic, but nevertheless cathartic computer-graphic free-for-all that climaxes “Crystal Skull,” I’m not sure I could tell you exactly what happened or why, anyway. Suffice it to say that any movie that successfully cribs from Lau Kar-Leung’s 1970s kung fu chestnut “The 36th Chamber of Shaolin,” Byron Haskin’s ’50s Amazonian potboiler “The Naked Jungle,” and Haskin’s 1953 version of “War of the Worlds” is okay in my book.

Though it was a hackwork cut-and-paste accident waiting to happen, “Indiana Jones and the Kingdom of the Crystal Skull” has turned out to be wide awake and engaging well beyond expectations. Lovingly designed and sturdily constructed, it forms a bridge uniting the times it fictionally depicts with the expertly made genre entertainments that inspired it and, most important, the summer of 1981, when “Raiders of the Lost Ark” knocked the moviegoing world’s collective socks off.