When, in the process of testing his newest time machine, Professor von Volt accidently brings a triceratops, Helen of Troy, Attila the Hun, Charlemagne, and Christopher Columbus to present day New Mouse City, it is up to Geronimo and his friends to return them all to their own times and places--without being eaten by a T-Rex or skewered by Trojan warriors.

Geronimo Stilton travels back in time to the ice age, ancient Greece, and Renaissance Italy, where he experiences wild historical adventures.

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.