A loyal, loving and intelligent dog travels many miles and hundreds of years searching for his lost owner. Both man and the dog are immortal following his master's discovery of a 'fountain of youth' type substance. The story explores not only the changes wrought in society by time, but also the pleasures and perils of immortality.
The historical aspects of the book were interesting, as man and dog experience the Renaissance and the Enlightenment as well as the devastation of the Napoleonic Wars.