When photographs of Peanut the dinosaur appear on the Web, Frank's father arrives in Wyoming with a story about the prehistoric reptile he saw nearby twenty years earlier.

"When a cave boy gets a 'puppy, ' things don't quite turn out as he expected"--

Fifth-grader Ronnie and Ms. Lernin tour the Cenozoic Era, where they encounter three kinds of mammals--monotremes, marsupials, and placental mammals--and other animals with which they shared the Earth.

All the mammoths have fled Old Mouse City! It's a total cat-astrophe! Not only because mammoths are valuable allies of the cavemice, but also because without them, the cavemice can't make mammoth milkshakes, their delicious national drink. Geronimo Stiltonoot must embark on a daring journey to find the mammoths...and avoid going extinct before he gets back!

Surprises are in store as Stink excavates his backyard in search of a relic from an extinct beast -- and Judy lends him a little sleight of hand. Mega-chomp! Stink wants to make the find of the century. He's on a dig, dig, digging quest in his backyard to find a tooth from a saber-toothed cat, otherwise known as a Smilodon. Why not? Two kids in Michigan found a mastodon bone in a backyard stream, and a girl in Great Britain found a pterosaur bone....

"Geronimo Stilton's ancient ancestor Geronimo Stiltonoot is back in another prehistoric adventure! It's the annual cavemouse sports competition! This year, Tiger Khan and his saber-toothed henchmen want to enter the games. They call a truce with the cavemice during the tournament ... but when their flag goes missing, Tiger Khan is furious. Can Geronimo Stiltonoot track it down in time to keep his fur intact?"--