Ranger, the time-traveling golden retriever, is back for the second book in Kate Messner's new chapter book series. This time, he's off to save the day in ancient Rome! Ranger is a golden retriever who has been trained as a search-and-rescue dog. In this adventure, Ranger travels to the Colosseum in ancient Rome, where there are gladiator fights and wild animal hunts! Ranger befriends Marcus, a young boy Ranger saves from a runaway lion, and Quintus, a new volunteer gladiator who must prove himself in the arena. Can Ranger help Marcus and Quintus escape the brutal world of the Colosseum?