When Mark Doty went looking to adopt a small dog, a cuddly creature who might comfort his terminally ill partner, Wally Roberts, he was surprised to find himself returning home from an animal shelter with a full-grown golden retriever, a dog whose "absolute openness of regard", and paw gently offered through the bars of a cage, proved irresistible to him. Beau, as the retriever was called, was so malnourished and in need of care that he was initially mistaken for a different breed, and Doty soon found himself attending to the constant needs of a dog starved for attention and a man confined to his bed. But the new member of the household, which also included Arden, Doty's black retriever, managed to provide a measure of comfort to everyone; as Wally neared death, Beau rushed headlong into his new life.

Dog Years is the story of Doty's life with Arden and Beau, two retrievers who, each in his own way, leave a profound mark on him: Arden, who likes sleeping outdoors, even in the rain, who is observant and contemplative, who is friendly and eager to please; Beau, blithe, snatching the glove from his master's hand and running away with it, a mischievous gleam in his eye, always full of daring and bounding toward his next source of amusement.

As his time with the dogs reaches its end, Doty must face the difficult realization that to deal with death is to accept it as the utter loss of an irreplaceable value. To grieve is to understand that, while we may carry on, while we may find new loved ones, the loss we have experienced is the disappearance of a unique individual who will never return, and this tragic disruption will become a permanent part of us.