The Time Traveler's Apprentice Book Two (Volume 2)

Simon Grant is returning a Roman bowl to the basement storage of the museum when the lights go out and he finds himself falling through a time portal, landing in an ancient Christian catacomb. So begins his adventures in Imperial Rome. Simon is taken in by a group of early Christians who must hide in the catacombs to escape Roman persecution. But a red-eyed demon now stalks the catacombs and threatens the group in their one place of sanctuary. Simon undertakes to catch this creature and finds himself entangled in a plot to assassinate the emperor of Rome. He must now focus on staying alive in the Colosseum, fighting for his life against a gladiator who has chosen Simon for his next kill.