The Iron Man arrives seemingly from nowhere, and his appearance is described in detail. He first appears falling off a cliff, but his various pieces reassemble themselves, starting with his hands finding his eyes and progressing from there. He is unable to find one ear, which was taken by seagulls earlier, and walks into the sea to find it. He eventually returns to the country and begins to feed on local farm equipment. When the farm hands discover their destroyed tractors and diggers, a trap is set consisting of a covered pit on which a red lorry is set as bait. Hogarth, a local boy, lures the Iron Man to the trap. The plan succeeds, and the Iron Man is buried alive. The next spring, the Iron Man digs himself free of the pit. To keep him out of the way, Hogarth brings the Iron Man to a scrap-heap to feast. The Iron Man promises not to cause further trouble for the locals, as long as no one troubles him. Time passes, and the Iron Man is treated as merely another member of the community. However, astronomers monitoring the sky make a frightening new discovery: an enormous space-being, resembling a dragon, moving from orbit to land on Earth. The creature (soon dubbed the "Space-Bat-Angel-Dragon") crashes heavily on Australia (which it is large enough to cover the whole of) and demands that humanity provide him with food (anything alive) or he will take it by force.

Terrified, humans send their armies to destroy the dragon, but it is unharmed by their weapons. When the Iron Man hears of this global threat, he allows himself to be disassembled and transported to Australia where he challenges the creature to a contest of strength. If the Iron Man can withstand the heat of burning petroleum for longer than the creature can withstand the heat of the Sun, the creature must obey the Iron Man's commands forevermore: if the Iron Man melts or is afraid of melting before the space being undergoes or fears pain in the Sun, the creature has permission to devour the whole Earth. After playing this game for two rounds, the dragon is so badly burned that he no longer appears physically frightening. The Iron Man by contrast has only a deformed ear-lobe to show for his pains. The alien creature admits defeat. When asked why he came to Earth, the dragon reveals that he is a peaceful "star spirit" who experienced excitement about the ongoing sights and sounds produced by the violent warfare of humanity. In his own life, he was a singer of the "music of the spheres"; the harmony of his kind that keeps the cosmos in balance in stable equilibrium.

The Iron Man orders the dragon to sing to the inhabitants of Earth, flying just behind the sunset, to help soothe humanity toward a sense of peace. The beauty of his music distracts the population from its egocentrism and tendency to fight, causing the first worldwide lasting peace.