Set during the Cold War in 1957, the film centers on a young boy named Hogarth Hughes, who discovers and befriends a gigantic metallic robot who fell from outer space. With the help of a beatnik artist named Dean McCoppin, Hogarth attempts to prevent the U.S. military and Kent Mansley, a paranoid federal agent, from finding and destroying the Giant. It is based on the 1968 novel "The Iron Man" by Ted Hughes (which was published in the United States as "The Iron Giant") and was scripted by Tim McCanlies from a story treatment by Bird.

References:
https://en.wikipedia.org/wiki/The_Iron_Giant