On Mars, the female babies are nursed by robots while the male babies are dumped in the junkyard under the command of Supervisor. They research Earth and finds that the boy Milo is raised by his Mom with love and discipline. The Martians come to Earth and abduct Mom, to use her brain to instruct the robots about how to raise children. However, Milo sneaks into the spaceship and comes to Mars. He meets Gribble, a young man that behaves like a child and together with the hippie Martian Ki and Gribble's friend Wingnut, they try to rescue Mom and bring her back to Earth. But Supervisor will give her best efforts to stop Milo and his friends.

Scott Calvin has been Santa Claus for the past eight years, and his loyal elves consider him the best Santa ever. But Santa's got problems (he's even mysteriously losing weight) and things quickly go south when he finds out that his son, Charlie, has landed on this year's "naughty" list. Desperate to help his son, Scott heads back home, leaving a substitute Claus to watch over things at the Pole. But when the substitute institutes some strange redefinitions of naughty and nice, putting Christmas at risk, it's up to Scott to return with a new bag of magic to try to save Christmas.

Three gymnasts become secret agents.

The mail in the north used to be delivered by dogsled, but the success of airplane delivery leaves Balto and the other sled dogs feeling neglected. However, when a delivery plane crashes on a mountain side, the sled dogs get the opportunity to show their worth. This story also prominently features Balto's son, Kodi, who was among the puppy litter that we met in Balto II: Wolf Quest.