The Book of Time by Guillaume Prévost. 2006.
Then his father vanishes. Sam waits for him to come home, but more than a week passes without a trace. He goes to the bookstore to search for clues. In a room he'd never seen before, he finds a strange red book called Crimes and Punishment During the Reign of Vlad Tepes, a stone statue with an odd circular indentation in it and a dusty coin with unreadable symbols. . . Eventually, with help from his cousin Lily, he is able to transport back home. Together, they learn more about the time-traveling statue and a man named Vlad Tepes, the inspiration behind the Dracula legends, who they believe is holding Allan in fifteenth-century Wallachia.