In this updated version of the 1951 classic sci-fi thriller, Keanu Reeves stars as an alien named Klaatu who's sent to Earth to warn the leaders of the world about the consequences of their dangerous ways. Joined by a heavily armed robot companion, Klaatu informs the people of Earth that the constant aggression carried out against one another has raised the ire of an alien species, which is now threatening to exterminate all of mankind.