When human astronaut Chuck lands on an alien planet, Lem and his robot companion Rover help him return to his spaceship and his home planet.

When Lem finds an alien hiding at the planetarium where he works, he is scared at first, but he agrees to help the alien, an astronaut from Earth named Chuck, recover his spaceship, which the army has locked up.

When human astronaut Chuck crash lands on an alien planet, Lem decides to help him return to his spaceship and his home planet.

When Chuck, an astronaut from Earth, lands on Planet 51, Lem and his alien-obsessed friends show him around, but then the army hears of Chuck's presence and plans to catch and kill him.

Astronaut Charles "Chuck" Baker lands on Planet 51 and finds it is inhabited by little green people who are happily living in a world reminiscent of 1950s America.