The story takes place around the late 1900s-1900s, in a time when steamers cross the world's harbor and air balloons are sent to the Arctic, as well as the last rainforests are mapped. 8-year-old Selma Traskvist's poor family gets wounded from his home. Selma meets the researcher Efraim von Trippelhatt, who works to build airships to prove the existence of the Christmas tree.