Sixteen-year-old Lem (Justin Long) lives on Planet 51, a white picket-fenced world reminiscent of a cheerfully innocent 1950s America. He is happy in his safe, predictable world and spends his time daydreaming about running the local planetarium and dating the girl next door, Neera (Jessica Biel).
One day out of the blue and millions of miles from his own planet, astronaut Captain Charles 'Chuck' Baker (Dwayne Johnson) lands his spaceship in Neera's backyard, right in the middle of a family barbecue! Unaware of his surroundings, he disembarks the ship reveling in his Big Moment. He plants his flag triumphantly and turns... only to find Planet 51's green-skinned inhabitants staring back at him bemused! He panics and flees, finding refuge quite by chance in the planetarium where Lem works.
When Lem and Chuck meet, they gradually overcome their mutual fear and strike up a friendship. Lem agrees to hide Chuck from the paranoid Planet 51 Army who are determined to capture the alien within their midst, convinced he is out to destroy them. But all Chuck wants to do is reach his spacecraft before it returns to Earth without him! So with the help of Lem and his friends, a pair of not-so-bright Planet 51 soldiers, and an excitable but trusty explorer robot, Rover, Chuck and the gang race to reach his spaceship before it's too late...
Studio: Alliance Films
Producer(s): Guy Collins, Ignacio Pérez Dolset
Screenplay: Joe Stillman
Official Site: www.planet51.com