Victorian era blue-blooded retired military officer, Captain W, who takes a working class family under his wing. Captain W, a decorated war veteran, is middle-aged, unmarried, and childless; he is an observer of life, rather than a participant. From the window of his study, he watches a young working-class woman, Mary A, as she is courted by and then married to her lover, a young painter with few prospects. Captain W, perhaps seeing a more innocent (pre-war) version of himself in the young man, anonymously assists the couple. Eventually, Mary and her husband have a child, David. Captain W falls in love with the boy who supplants imaginary Timothy, the son whom the Captain will never have. Eventually, the Captain's identity is discovered by Mary, who approves of his interest in her child. Much of the novel is a recounting of the adventures the man and the boy have in Kensington Gardens in London.