He's a golden retriever who has been trained as a search-and-rescue dog, but can't officially pass the test because he's always getting distracted by squirrels during exercises. One day, he finds a mysterious first aid kit in the garden and is transported to the year 1850, where he meets a young boy named Sam Abbott. Sam's family is heading west on the Oregon Trail, which can be dangerous. It's up to Ranger to make sure the Abbotts get to Oregon safely!

From the book