When Dino the Chow Chow dog's doggy door has become a time tunnel going back to the age of dinosaurs his owner and best friends crawl through to explore . and find themselves at the bottom of the food chain. Did I mention that the time tunnel is being caused by alien librarians? In this, the long awaited 5th book in the series, Dino and the kids run into psycho "birdosaurs", huge Stegosaurs, meat eaters, space pirates and other strange things you will never read in a history book.