Following the deaths of her husband and son, Helen Cartwright returns to her hometown in England after living abroad for sixty years. Her only wish is to die quickly and without fuss, and she retreats from the world into a life of dull routine. Then one winter night, a chance encounter with a mouse sets Helen on a surprising journey.

Because a mouse has teased Miss Moppet, that kitten thinks she will tease the mouse.

Geronimo and his friends participate in a treasure hunt set up by his rival and are determined to overcome all of its challenging obstacles, including tricky riddles and smelly dinosaurs. "En Petrópolis está a punto de comenzar el juego de la Búsqueda del Tesoro más superratónico de la Edad de Piedra. Valiéndose de una serie de pistas misteriosas y chocantes, Geronimo Stiltonut y sus amigos tendrán que resolver adivinanzas y otras pruebas...