A spooky[,] spine-tingling time travel adventure that takes a boy and his eccentric professor friend to the mysterious Byzantine Empire (Publishers Weekly) . . .[Description]Johnny Dixon is worried about Professor Childermass. The professor has always been an odd duck, but lately his behavior has been positively bizarre. Hes been talking to himself and stalking down the street with his collar turned up and his hat over his eyes, and now he wont return Johnnys calls. Johnnys afraid that the professors old age is starting to get to him, but he will soon find its something far more amazingand far more dangerous.The professor has discovered a trolley that can carry them five hundred years back in time, to the last days of the Byzantine Empire. In the dark and winding streets of Constantinople, he and Johnny confront crusaders, mystics, and thieves as they attempt to save the ancient empire from destruction at the hands of the advancing Turkish armies.Created by the award-winning author of The House with a Clock in Its Walls, Johnny Dixon is one of the most charming young heroes in literaturea spunky, bespectacled young man whose curiosity often gets him into troubleand his wonderfully warming friendship with cantankerous old Professor Childermass makes them an endearing detective team (The New York Times).