Geronimo's sister Thea Stilton narrates this action-packed adventure! The Thea Sisters have been invited to Egypt to participate in a fabumouse archeological excavation. They are helping to look for the legendary ancient Treasure of the Sun! A precious blue stone scarab may be the key to their search and they work enthusiastically to uncover the past but they also discover that thieves are after the hidden treasure. It's up to the Thea Sisters to stop them!