In this exciting installment of the Magic Tree House series, Jack and Annie are transported back in time to the bustling Roman city of Pompeii. Their mission is to find a lost library, but they soon realize they have arrived on the very day Mount Vesuvius is set to erupt. They must navigate the ancient streets, decipher clues, and race against time to escape the city before it is buried forever under tons of volcanic ash. This adventure blends history with thrilling suspense, offering a glimpse into one of history's most famous disasters.