An Iron Giant suddenly appears from nowhere. He is taller than a house, with feet that are each as big as a bed. He stalks the earth, devouring tractors and barbed wire, terrifying farmers and townspeople everywhere.

Depsite his insatiable hunger for metal, the Iron Giant is guite gentle and good-natured, though the thownspeople are too frightened of him to realize it. So they capture him and put him in a scrapyard, where he happily stuffs himself with stoves and bicycles.

The people forget about the Iron Giant until a big shadow blocks out the sun. A giant space-bat the size of Australia is hovering over the earth, ready to destroy it. The earth needs a champion. But who or what is big enough and brave enough to do battle with the hideous creature from outer space?