The film follows Graeme Willy (Pegg) and Clive Gollings (Frost), two geeky lifetime friends finally embarking on a years-in-the-making journey across America that starts at the San Diego Comic Con and is meant to conclude in Roswell, New Mexico. Before they get there, however, they witness a car crash, out of which crawls a rather congenial alien named Paul (voiced by Seth Rogen). After some shock and awe at the appearance of a real, live spaceman, Paul explains to the guys that he needs help getting across the country in the hopes of catching a ride back to his planet. Not surprisingly, Graeme and Clive agree to help.

Although many of the movie's jokes are based around the duo's fish-out-of-water Britishness in the middle of the American midwest, it's very apparent throughout that Paul has been written with the American audience firmly in mind. Unfortunately, the broader sensibility basically means plenty of fart jokes, slapstick comedy, a mild fascination with profanity and the repeated insinuation by lesser characters that Graeme and Clive might be gay lovers. The duo also heap on the references like there's no tomorrow: nods to Close Encounters, E.T., and a bucketful of Star Wars dialogue are tossed in throughout, but few of them pack the required subtlety or surprise (only a hat-tip to Aliens seemed perfectly timed). It's as if Paul was in front of cameras on the first draft thanks to Pegg and Frost's reputation.

Which is not to say that reputation is unearned or absent; a Pegg/Frost "first draft" probably still packs more wit than some people's fifth. Although they're probably just a touch too old for the roles they've written (at 41, it's time for Pegg to hang up his nerd hat as a performer), they're more than able to make Graeme and Clive a likable set of hosts. Even better, they've surrounded themselves with a supporting cast that's basically the definition of "foolproof", some of who may contribute more to Paul's escape from mediocrity than the dynamic duo themselves. Kristen Wiig adds a much-needed dose of both "sweet" and "cute", lanced with a perfectly-delivered thread of newly-discovered crudeness. Bill Hader and Joe Lo Truglio play moronic FBI agents incompetently trying to catch Paul before the cold, no-nonsense Agent Zoil (Jason Bateman) gets there first with professional cartoonishness (especially Hader, still one of Hollywood's most underrated comic actors). Most importantly, Rogen, whose voice may have seemed too easy as a laid-back interstellar party guy, finds a soft, accepting side to Paul that holds the whole movie together. Paired with the visual effects, he's a character worth building a film around, and an integral, under-sold piece of the film's charm.

As director, Mottola brings a similar "anything goes" attitude as Paul to the table, feeling free to lounge around to whatever joke or setting the script dictates without too much fuss or setup. Sometimes it works (the explosion of a farmhouse seems startlingly large scale) and sometimes it doesn't (the movie often feels like it plays its cards too early, telegraphing jokes and plot developments). Still, Paul is a fun ride: the movie may be firmly caught within the grasp of Earth's gravitational pull, but it's still a funny, entertaining trip from one side of the country to the other.