Vacation Under the Volcano

In their first adventure as Master Librarians, Jack and Annie go to the
city of Pompeii to bring back an ancient story that is in danger of being lost
forever. Little do they know they are saving the myth of Hercules! But before
they can find it, the town's volcano erupts in a mighty explosion. Just when
things look hopeless, Jack and Annie get some unexpected help from a certain
mythic hero - and the rest, as they say, is history.