What do you get when you assemble a cast of first-rate young actors with seasoned comedy professionals like Steve Coogan and “Saturday Night Live’s” Molly Shannon?

In “What Goes Up”, a quirky independent summer flick that opens this Friday, the answer is not what you might be expecting.

Coogan, a British comedian who grew up in an Irish family in Manchester, plays Campbell Babbitt, an emotionally damaged man who travels to New Hampshire to write a news report about the hometown of the first teacher to be selected for a Space Shuttle mission. Since “What Goes Up” is set in the late 1980s, we instantly realize that the Shuttle will be named Challenger and that the mission will end in an era-defining tragedy.

But before we have time to take in this fact, Babbitt discovers that his old college buddy has recently committed suicide. Soon he inherits the small group of grief-stricken students his dead friend taught at the local high school. Without their adored mentor they’re rudderless, immediately looking to Babbitt for a replacement.

Coogan can always be relied upon to deliver an edgy performance, and in “What Goes Up” he steals every scene he appears in. But in the end an underwritten script and often completely confusing direction undermine all his best efforts.

On the surface “What Goes Up” looks like a classic 1980s teenage angst film in the style of “The Breakfast Club” or “Pretty In Pink,”  but its over the top quirkiness also resembles classic high school outsider tales from the 1990s like “Election.” In the end you can see all of its influences, and also notice that it has failed to carve out its own niche.

As the dysfunctional students that Babbitt encounters, Hilary Duff, Josh Peck, and Olivia Thirlby do their best with the kind of over familiar teenage characters that populate this movie and seem to have been crafted to drive the storyline rather than take on any independent life of their own.

Duff and Thirlby are particularly underserved by their cutout characters. As a secretly pregnant teen who’s brimming with anger and resentment, you’d expect that Thirlby’s emotionally battered character would merit more screen time and at least some explanation, but it never comes.

Duff is also saddled with a flatfooted character (the references to “Romeo and Juliet” are particularly forced) who turns out to be less interesting than she at first appeared.

But what’s most striking about “What Goes Up” is how inconsistent it is from start to finish. At times it presents itself as a straight up if morally challenged comedy, and then at other times it tries to become an insightful period drama. Unfortunately the collision between these two opposing tracks is unavoidable, and the film suffers mightily for it.

Leave it to “Saturday Night Live’s” Shannon to carve out her own niche in this bewildering mess of a film. As the terrifyingly pedantic local school teacher directing the annual musical, Shannon sets her own tone and at times seems to be performing in her own film. With her 1970s French flip and her withering stares, she’s an indication of the heights that “What Goes Up” might have scaled with a bit of coherent direction and a much stronger script.

Actress and singer Duff’s core audience of tweens and twentysomethings may turn up to watch this spectacular misfire, but it’s more likely to sink without trace. If it gets her out of the Disney Channel ghetto she’s been working in toward the more adult roles she’s obviously angling for it will have served its purpose, but she’ll certainly have paid her dues in the process.

The utterly confusing plot, the bizarre tonal shifts and the uneven acting styles may scream cult classic, someday, but even hardcore film collectors will want to draw a veil over this deeply disappointing flick.

Even Peck, an exciting new talent, cannot break out of the imprisoning triteness of the script to deliver the kind of performace he’s actually capable of. 

Traditionally, in films like “What Goes Up” the older hero usually ends up learning a thing or from his younger associates. But in this film Coogan’s character, like the teens he encounters, walks away empty handed.