It is Christmas Eve. The big hi-tech sleigh, the S-1 is to deliver two billion presents on Santa's 70th mission. Meanwhile, Arthur gets a letter from a girl from 23 Mimosa Avenue, Trelew, Cornwall, England, saying that she wants a Pink Twinkle Bike for Christmas. The S-1, which is the answer to every child's question: How does Santa deliver all those presents in just one night, travels seven million miles around the world delivering the gifts. However, during a delivery operation, when one child wakes up and almost sees Santa, an elf inadvertently presses a button, causing a present to fall off a conveyor and go unnoticed. A crazy wrapping elf called Bryony discovers the gift and Arthur is alarmed to discover that it was the present for Gwen Hines, the Twinkle bike. Grandsanta, proposes delivering the gift using Evie, his old wooden sleigh, and the descendants of the original eight reindeer, forcefully whisking away a reluctant Arthur and a stowaway Bryony. They get lost, lose reindeer, and land in danger several times, ultimately being mistaken for aliens and causing an international military incident. Can Arthur, with the help of Grandsanta and Bryony really be the heroes of the night and deliver the missing present before Gwen wakes up, thus saving Christmas?