Ten-year-old Leo loves being a newsboy in San Francisco -- not only does he get to make some money to help his family, he's free to explore the amazing, hilly city as it changes and grows with the new century. Horse-drawn carriages share the streets with shiny new automobiles, new businesses and families move in every day from everywhere, and anything seems possible. But early one spring morning, everything changes. Leo's world is shaken -- literally...

Jack and Annie are all shaken up! The magic tree house whisks them back to California in 1906. As soon as they arrive, the famous San Francisco earthquake hits the city. Can Jack and Annie find the final writing they need to help Morgan save Camelot? Or will San Francisco be destroyed first?