Just when Santa and the elves thought they'd completed another successful Christmas present delivery drop, a siren goes off at the North Pole's Mission Control. Red alert! A present has been left behind and a child forgotten! It's up to Arthur, Santa's clumsy, technologically-challenged son, and his slightly batty grandpa, Grandsanta, to deliver the gift and save the day. But this team is off to a rough start—Arthur is afraid of heights and fast-moving vehicles, Grandsanta's trusty maps are really old, and their newest herd of reindeer has never flown before. Arthur had better find some old-fashioned Christmas magic if he's going to save Christmas!