Ranger is a golden retriever that has been through the training required of search and rescue dogs. Unfortunately, he can’t pass the test required to be an official search and rescue dog. He keeps chasing squirrels and flunking the test. Ranger found an old metal box in the back yard. This box takes him to different places in time. On one trip he went been back in time to the Oregon Trail and this time Ranger has been transported to the Colosseum in ancient Rome. This is the place where gladiators fight and wild animals are turned loose in the ring. Ranger saves a young boy named Marcus from a wild lion that gets out of its’ cage at the Colosseum. Marcus has a friend named Quintus who is a new gladiator. Ranger must help them both survive the tests and fighting that takes place at the Colosseum.