F

After suffering through “Dumb and Dumberer: When Harry Met Lloyd,” you might be tempted to check your calendar. Studios usually hold their very worst summer movies until the dog days of August, so you might think that somehow you’ve lost a couple of months. Rest assured, it’s still only June; Columbia started the blockbuster season early with “Spider-Man” last year, and now New Line has with a single stroke pushed up the late-summer doldrums, too.

You don’t go to a prequel to the 1994 Jim Carrey-Jeff Daniels smash expecting refined entertainment, of course. After all, the original–which pretty much put the Farrelly Brothers on the map–was about as low-brow as you can get. Still, though it amazes some of us that anybody would want to sit through it more than once, the first picture had a certain dopey innocence that made at least parts of it sporadically amusing. And it was a breakout film for Carrey. “Dumberer,” however, has no innocence whatever; it’s a calculated gross-out machine, made by people (with the exception of several of the myriad producers) who had no connection with the earlier flick except for having watched it all too frequently. In this case the unremitting stupidity has almost no redeeming moments of real fun. It’s a dismal movie, a true endurance test for any viewer with an IQ above those of its two lead characters.

To call the “plot” wafer-thin would insult a wafer. After a brief prologue sketching Harry Dunne’s unusual birth (cue in the grossness) and youth, we’re shown him as a doofus teen literally bumping into Lloyd Christmas (and chipping the guy’s front tooth) on the first day of high school. The two become dim-bulb buddies at once, and straightaway become the means by which crooked Principal Collins (Eugene Levy) and his romantic cohort lunch lady Ms. Heller (Cheri Oteri) aim to bilk cash from a scholarship program by setting up a phony special ed class and running off to Hawaii with the money. Before long Harry and Lloyd have recruited a small group of students looking for a thoroughly undemanding course to join them. The only “plot” that follows involves sexy co-ed Jessica (Rachel Nichols), an aspiring investigative reporter, involving herself with the boys in order to get the goods on the principal’s malfeasance. And, of course, they help her without realizing it, hah-hah.

This so-called scenario, however, is just a thin thread on which to hang a chain of episodes in which Derek Richardson, as the lethargic Harry, and Eric Christian Olsen, as the manic Lloyd, engage in verbal and physical dopiness. Though you have to admire the way Olsen positively throws himself into his part, doing a strenuous Carrey impersonation (Richardson, by contrast, is rather bland), the shenanigans are far from rip-roaring. The best bit is one that involves a grubby convenience-store clerk (Brian Posehn) who’s intolerant of the boys’ inane game of tag (though the topper to this confrontation is both clumsily staged and depressingly unpleasant). Otherwise, things never catch fire. An effort to refashion the first picture’s infamous toilet sequence for the young Harry is more repulsive than hilarious (it doesn’t help that Bob Saget has been recruited to shout an excremental term as often as possible to generate laughs, though it must be said that his closing line–“It’s all s**t”–seems pretty appropriate under the circumstances). Other would-be set-pieces fall similarly flat. The secondary characters can be divided into two categories–dull and duller. The lead duo’s classmates are played by likable enough young actors–Elden Henson, Michelle Krusiec, Shia LaBeouf, William Lee Scott–but they have little to do. Even Luis Guzman can make no impression as Lloyd’s janitor father, while Levy and Oteri, canny performers both, are defeated by material of such crushing obviousness that they come over as obnoxious instead of raunchily amusing. The desperation of the makers becomes apparent about an hour in, when they insert a montage of snippets from sequences we’ve already seen to show us how Harry and Lloyd have formed a bond; the repetition–a sort of lowlights reel–only serves to remind up how lame the material was in the first place. “Dumb and Dumberer” is crummy from a technical perspective, too; the production looks chintzy and threadbare throughout.

As a final indignity the makers include, during the final crawls, a selection of out-takes–a bad practice in almost every instance, but especially misguided here, since the bits prove even more leaden than what’s preceded, wretched as the movie itself was. You could say that with them, “Dumb and Dumberer” just goes from worst to worster.