Anyone who's been anticipating the day that Mel Brooks would get around to making a proper follow-up to History of the World, Part I need wait no longer. With Year One, Harold Ramis has effectively filled that massive, lingering gap in modern cinema by creating a film that similarly takes a long look at human history and filters its recollection of times and places through decidedly comedic sensibilities.

Unlike its predecessor, however, there is a vast wealth of similar material preceding it—with or without Brooks' comparatively groundbreaking film—that unfortunately makes its sense of the past, cinematically speaking, short-sighted at best. Historical accuracy aside, it's silly without being substantive and yet painless without being profound—which makes Year One seem destined to earn the dubious distinction of being the one movie released in the summer of 2009 that made another trapped-in-time adventure, Land of the Lost, seem like a masterpiece by comparison.

Jack Black and Michael Cera star as Zed and Oh, two misfits who weren't destined to either hunt or gather, which sadly happen to be the only two jobs available for the men in their tribe of barbarians. After Zed eats from the Tree of Knowledge of Good and Evil, he and Oh are banished from their village, effectively squashing their plans to woo two of the tribe's comely females, Maya (June Diane Raphael) and Eema (Juno Temple).

Convinced that his mischief-making ingenuity is prophesied by the gods, however, Zed leads Oh into undiscovered territory, where they encounter new cultures and civilizations, eventually arriving at the kingdom of Sodom. Despite its appealingly colorful history, the city proves mysterious and dangerous, and Zed and Oh soon find themselves fighting not only for their own freedom but for the lives of their tribesmen—especially the women.

While the past three decades have seen more than its share of prehistoric comedies, the time seems right—no pun intended—for a film that deconstructs the conventions of period adventures and sword-and-sandal epics. (Indeed, last year's 10,000 B.C. was a parody of itself without even realizing it.) As the smart-aleck sidekick has moved to the center of many action movies, observing and commenting on the implausibilities and unlikelihoods even as they unfold around him, it seems only natural that a similar migration would happen in other genres. Moreover, these quasi-biblical movies already seem so far removed from our own experiences, much less our contemporary values, that their stories would appear ripe for comedy, if only someone with that contemporary point of view could only be up there on screen!

One imagines this is exactly what Ramis and company thought when they conceived Year One, and then promptly forgot everything else they knew about real characters or storytelling. Some scenes begin and build and then go nowhere; others trail off after a single successful joke without trying for others. What works is Jack Black and Michael Cera's indefatigable penchant for observing simple and yet intimate truths in situations that would otherwise be big, archetypal and otherwise implicitly accepted; although both are essentially exercising well-established personas they've created in better films, Cera expertly sizes up his situation, whether he's basking in romantic rejection or recuperating after a cougar attack, while Black elevates his moronic sense of self-importance to monomaniacal proportions.

What doesn't work, unfortunately, is Year One's half-hearted obligation to Zed and Oh's hero quest, which admittedly sort of must exist in order to give the film a semblance of shape but works at cross purposes to the characters' comments, random punchlines and non-sequiturs. Naturally, this is also the element that takes over the film toward the end, which means that the humor is sort of shoehorned into action sequences and big set pieces that are otherwise pretty unfunny. As a whole, nothing really comes together—again, as if there were ideas about the way in which to make this kind of movie, but not what to do with those ideas, and certainly not how to plug them into a feature-length story that takes place in A.D. 1.

Then again, Judd Apatow has never quite excelled at constructing strong narratives, only connecting weak ones with strong characters; as this film's producer, he enlisted the best talent both on screen and behind the cameras but applied his style to a structure—not to mention a genre—to which it's spectacularly unsuited. But the failure of Year One is no one person's fault; rather, it's just sort of a collective misfire from a bunch of folks who do a lot of things right but can't quite manage to do them together.

Ultimately, Year One is by no means a first for anyone involved. Whether it's merely a mediocre addition to someone's filmography, an all-around bad movie, or a commercial bomb for the ages, it isn't so irredeemable that it deserves to be their last—even if it nevertheless goes down in history as all three.