Ed Helms seems to like road trips. His last major movie, “The Hangover,” depicted a debaucherous weekend trip to Las Vegas in which he consumed copious amounts of alcohol and drugs, got cozy with a prostitute, and was savagely attacked by a stranger. Helms replicates all of these feats in “Cedar Rapids,” his newest vehicle—directed by Miguel Arteta—but this road trip to the sleepy eponymous Iowa city lacks the drive of its predecessor. Although successful in some respects, “Cedar Rapids” is to “The Hangover” as Cedar Rapids the city is to Las Vegas: much less energetic and much more forgettable.

Helms plays Tim Lippe, a geeky insurance agent who has lived in Brown Valley, Wis., all of his life. Not that he wants to leave; his greatest aspirations are to build a little green house in his backyard and raise a family. But after a colleague dies in a suspicious choking accident, Lippe is called upon to represent his company at a convention in Cedar Rapids.

The rest of the movie largely consists of Lippe trying to deal with and understand the workings of the foreboding outside world. He fails to comprehend both the standard practices of the city’s life—boarding a plane, checking in at a hotel—as well as the people who inhabit it. He is bewildered by the come-ons of fellow conference attendee Joan (Anne Heche) and the aggressive and free-for-all attitude of rival agent Dean Ziegler (John C. Reilly). But of course, while trying to stay out of trouble, he entangles himself in several messy adventures and engages in the sort of behavior he originally detested. By the end of Lippe’s coming-of-age story, he has made a couple of great friends, fallen in love twice, dabbled in hard drugs, and triumphed in a battle of good versus evil.

Although all of this is standard fare for a comedy, “Cedar Rapids” doesn’t seem to be trying very hard to get laughs. The punch lines are minimal, and the movie dedicates a large amount of time to Lippe’s character development and relationship trials. The result is a movie uneasily balanced between farce and a genuine mid-life crisis drama. This confusion makes for an uncomfortable viewing experience—Tim Lippe is a fairly likable and honest guy with good intentions, and viewers feel guilty laughing at his mistakes and tribulations. Are they meant to mock him or identify with him?

Perhaps the movie’s main issue is Helms himself, who, although excellent in his supporting roles on “The Daily Show” and “The Office,” isn’t quite engaging enough to carry an entire film on his own. In “The Hangover,” he shared the spotlight with the arrogant Bradley Cooper and the eccentric Zach Galifianakis, allowing him to inhabit his shy and underwhelming character without feeling pressure to create comedy on his own. In “Cedar Rapids,” by contrast, he’s expected to provide the laugh lines almost single-handedly, and the results are spotty.

That said, Helms gets a lot of help from Reilly—Helms’s cutthroat competitor—whose charisma provides most of the energy in a film populated by largely uninspired performances. Reilly, like Helms, is used to playing supporting roles (“Chicago,” “Talladega Nights,” “Step Brothers”), and his own feature, “Walk Hard: The Dewey Cox Story,” was largely a failure. But in “Cedar Rapids,” he looks quite comfortable as the crude and alcoholic Dean “Deanzy” Ziegler, reveling in cringe-inducing puns and body humor; some of the best moments in the film are his interactions with his roommate Wilkes (Isiah Whitlock Jr.) and his superior Orin Helgesson (Kurtwood Smith).

“Cedar Rapids” has a modest cast and modest aspirations, and fairly portrays the Midwestern city vibe of its titular city. At the same time, it is hurt by its internal thematic contradictions and second-rate performances. “I think I did a fair to middlin’ job,” Wilkes comments proudly to Lippe and Ziegler at one point in the film. The same could be said about “Cedar Rapids.”