At Uncle Blue's house, Petter and Lotta get to go to their very own school. Their teacher teaches the children everything under the sun. They play cowboys and Indians and learn how to build an igloo. When Aunt Brown's birthday comes around, they prepare a surprise, with a treasure hunt and ghost games. Of course, it turns out to be a very successful birthday!

Petter and Lotta are excited to celebrate Christmas for the first time with a real Christmas tree and Christmas presents.