Paul
In 2009, Graeme Willy and Clive Gollings (Simon Pegg and Nick Frost) are two English comic book nerds and best friends who have travelled to America to attend the annual Comic-Con convention in San Diego, California. Afterwards, the two take a road trip in their rented RV to visit all the sites of major extraterrestrial importance in the southwest USA. At one stop in Arizona, Graeme and Clive visit the Little A'Le'Inn where two hunters confront them, assuming they might be homosexual. In a hurried leave, Clive accidentally reverses the RV into the hunters' truck, leaving a dent.
Later that evening, Graeme and Clive see headlights racing up behind them and, believing it to be the hunters, they speed off in their RV. Eventually, the vehicle catches up and they realize it's just a car. However, the car suddenly wrecks up right in front of them, and rolls off the highway. When Graeme and Clive investigate the crash, they meet and discover an alien named Paul (voiced by Seth Rogen) who is in desperate need of their help.
Although shocked by the appearance of Paul, Graeme agrees to give Paul a ride, but Clive is not happy about the idea. Later, Lorenzo Zoil (Jason Bateman), a shady government agent, arrives at the site of the crashed car and informs his mysterious female superior over the radio that he's closing in on Paul, and she recommends using local law enforcement as back-up. Zoil then recruits two inept FBI agents, Haggard (Bill Hader) and O'Reilly (Joe Lo Truglio), to aid in his mission, without telling them the nature of their target.
Graeme, Clive and Paul pull into a motor park run by Ruth Buggs (Kristen Wiig), a creationist Christian, and her abusive and controlling father, Moses (John Carroll Lynch). The trio bond around their campgrill, and Paul reveals that, ever since he was captured by the government, he had been advising them in all manner of scientific and sociological achievements, including giving Steven Spielberg the idea for E.T. and inventing the character of Fox Mulder. However, he discovered that he had outlived his usefulness as a receptacle of knowledge, and the government was now intending to surgically remove Paul's brain in an attempt to harness his abilities. With help from a friend inside Area 51, Paul sent an S.O.S. to his home planet, and his people are now en route to pick him up. The government pushed up the schedule for Paul's surgery, however, prompting his rapid escape.
The next morning, Paul inadvertently reveals himself to Ruth, and the trio are forced to kidnap her and make a hasty escape. Paul then shatters Ruth's faith by sharing his knowledge of the universe via telepathic link; at first horrified, Ruth suddenly becomes eager to sin, which her father had raised her to fear doing. She initially doesn't trust Paul, but he heals her eye, as she has been blind in it since the age of four.
Meanwhile, Zoil, Haggard, and O'Reilly talk to Ruth's father, who claims she was abducted by a 'demon'. Haggard finds a drawing of Paul that Graeme did, and becomes suspicious of Zoil's motives, especially after he accidentally overhears Zoil reporting to his mysterious supervisor over the radio. When Graeme, Clive and Ruth encounter the same pair of hunters from earlier, and are saved by Paul, Haggard later has his suspicions confirmed by showing the hunters Graeme's drawing, which elicits a fearful response.
Whilst stopping in a small town, O'Reilly accidentally encounters Paul in a comic book shop, prompting the foursome to flee. When Haggard and O'Reilly tell Zoil what they saw, he pulls a gun on them, and orders them to return to headquarters, before going after the RV on his own. Contrary to his orders, however, the two FBI agents follow Zoil in the same direction.
Eventually, Paul reveals his intention to return to the girl whose dog he crashed his ship on in 1947 and who subsequently saved his life, who is now an old woman, Tara Walton (Blythe Danner). After spending her life being ridiculed for what she said she saw, Tara seems grateful to see that Paul simply exists. She turns her gas cooker on to make tea, but is interrupted by Haggard and O'Reilly on one side of the house, and Zoil on the other. As the motley crew escapes and drives off with Paul, O'Reilly shoots at them, and the gas ignites, destroying the house. A winded Zoil tries to follow, but Haggard takes off first, running Moses (who'd also been tracking the RV) off the road, and catching up to the RV. However, thanks to an error of judgement, Haggard accidentally drives off a cliff, and is killed, leaving Zoil in hot pursuit. He reassures his superior that he'll have Paul within an hour, but she declares herself tired of waiting, and informs Zoil that she's ordered a military response, prompting Zoil to shoot his radio.
When Paul, Graeme, Clive, Ruth and Tara arrive at the rendezvous, they set off a signal and wait. Eventually, eerie orange lights show up over the surrounding trees, and everyone believes that it is Paul's race. However, it is an army helicopter, with 'the Big Guy' (Sigourney Weaver) on board, Zoil's shadowy superior. As she and three troops move to shoot Paul, Zoil arrives, and it's revealed that he was Paul's inside contact who had helped him to escape. Zoil disarms the men, but is shot in the shoulder. Tara punches out 'the Big Guy', but Moses appears with a shotgun and shoots Graeme dead. Paul heals him, but inflicts the damage to himself (a possible side effect of his healing powers mentioned earlier in the film). Paul then collapses, exhausted. For a while, the other characters stand around his apparently lifeless body sprawled on the grass. Then, coughing, Paul props himself up, having healed himself. 'The Big Guy' regains consciousness, but is immediately crushed by the arriving alien ship. Paul begins to depart and informs Tara that she is going with him to live a better life and bids farewell to his friends hoping to meet them again one day.
Two years later. Graeme, Clive, and Ruth are shown again at a comic convention, promoting their new mega-successful comic book, "Paul". O'Reilly is also shown to have survived the house explosion.
