The mouse world has changed, smart mice study at mouse universities. Inquisitively, they follow the inventions of humans. Thanks to an old yellowed diary note from his great-grandfather, the young mouse Pete learns of a treasure that is said to have disappeared at the bottom of the sea. With the help of his mouse professor, he now does everything in his power to recover this treasure. The two not only experience a fantastic adventure, but also make a discovery that will enlighten mankind forever. Torben Kuhlmann's great enthusiasm for science fiction and adventure stories takes him below sea level this time. Kuhlmann's drawing care and his love of detail come to the fore in breathtaking images. Completely new visual worlds open up to the viewer. The third volume of the Mouse Adventures is a consistent continuation of Kuhlmann's Illustr.