The Trolley to Yesterday

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. He's been talking to himself and stalking down the street with his collar turned up and his hat over his eyes, and now he won't return Johnny's calls. Johnny's afraid ...