On December 17th, when Theo Bartlett and his little sisters, Olivia and Sophie, went into the woods behind their house to investigate the explosion they heard, the last thing they thought they'd find would be Santa Clause's sleigh, chock full of presents and an unexpected stowaway - a little green, ten-year-old alien named Gug! The Bartlett kids quickly realize that Gug and Santa have somehow switched places! Gug is here on earth while Santa is stuck on a spaceship somewhere in the galaxy! Theo, Olivia and Sophie know they only have one week to reunite their new alien buddy with his family while figuring out a way to get Santa back in time to save Christmas. And this all has to be done while keeping Gug secret from their friends and family! That alone would require a Christmas-sized miracle, but when you throw in an alien-hunting Mall Santa, an Air Force pilot with a grudge against St. Nick and the biggest bully at school (who is intent on making the Bartlett children miserable), their task seems darn near impossible! Will the siblings and Gug be able to save the day, or will millions of children wake up to find no presents under their trees Christmas morning? Kids of all ages, as well as their parents and grandparents, will love this fast-paced, fun, out-of-this-world, instant holiday classic.