Late one Christmas Eve, a boy boards a mysterious train: The Polar Express bound for the North Pole. Once there, Santa offers the boy any gift he desires. The boy asks for one bell from the harness of a reindeer. The bell is lost. On Christmas morning, the boy finds the bell under the tree. The boy's mother admires the bell, but laments that it is broken — for you see, only believers can hear the sound of the bell.