From the Jurassic period and the dinosaurs, to a medieval castle, Geronimo Stilton and a few members of his family embark on an adventure through time in Professor von Volt's new time machine, the Mouse Mover 3000.

Join Geronimo on a whisker-tingling trip through history! I, Geronimo Stilton, was so excited to travel on my third journey through time! Professor Paws von Volt had invented a portal to take my family and me to the past. On this trip, we visited the Ice Age, ancient Greece, and the Renaissance. I encountered wooly mammoths and enormouse bears, wrote and starred in a play, and even helped put a bad guy in prison! But then the portal started malfunctioning...

Professor von Volt plans to send Geronimo and his time traveling friends back to King Solomon's court to borrow a ring that supposedly will restore harmony to Mouse Island and balance the environment--but they soon find themselves taking an unplanned detour through Napoleon's court, a Viking village, and the Minotaur's labyrinth, before finally arriving before the wise King.

When pirate cats threaten Mouse Island, Professor von Volt sends Geronimo Stilton and his friends back through time to ancient Greece, Atlantis, and Stonehenge to try and find out how ancient civilizations were able to find peace and avoid war--only to find that the key to peace was under their whiskers the whole time.