At first, Mary the old wagon horse is only one of the many animals and people who drift in and out of Magnus' lonely little orbit. Chief among them is a local delivery boy, Matthew, who is ""like a big brother to Magnus,"" compensating somewhat for his lack of playmates and pets in the busy Gothenburg street. When Mary is evicted from her stable, the two conspire to find her a new home. But a big city has little hospitality for horses, and the boys endure a dark, dangerous ride to Matthew's farm before they find shelter. It's an oddly structured little book, slow-paced vignettes for two-thirds of the way, and then a rush of adventure. Magnus is young--seven or eight, perhaps--and acts younger. The loneliness of a shy, imaginative child surrounded by an uncaring, bustling milieu, is nicely conveyed, but his sudden adjustment is not convincing: after his midnight ride, Magnus is a hero, welcomed by the very children who had taunted him.