A man walking near his house spots a stray dog he recognizes: the scruffy female who used to be the secret lover of his own dog, Tommy, now gone for two years. He admits she was never attractive, with her mangy black coat and swollen teats, yet she mattered because Tommy loved her. Now she is old, thin and limping, her fur falling out in patches. He wonders whether anyone will notice when she dies.
Then the poem turns. The speaker describes his own bald head, aching knees and pounding heart, and catches his reflection in a shop window: an old man dragging his feet. He has been describing himself all along. The question about who will miss the dog quietly becomes a question about who will miss him. The ending is plain and sad, as the dog turns right and he turns left. The mood is tender, lonely and unsentimental, with a calm acceptance of aging and loss.