Mr. Salteena is an elderly man of forty-two who lives with a seventeen-year-old girl named Ethel Monticue and nurtures a secret desire to become a proper gentleman. He visits his wealthy and pretentious friend Bernard Clark, who lives in a grand house complete with haughty servants and dubious ancestors. Observing Bernard's sophisticated lifestyle only deepens Salteena's insecurity about his social standing.
Bernard takes a strong liking to Ethel and decides to take her up to London for a season of gaiety at the Crystal Palace. Meanwhile, Salteena seeks out the Earl of Clincham in the private compartments of the Crystal Palace to receive instruction in the ways of the aristocracy. Through the intercession of the Prince of Wales, Salteena eventually secures a coveted position galloping behind the royal carriage in green velvet knickerbockers.
Back in London, Bernard and Ethel's romance progresses during a trip to Windsor, where Bernard proposes marriage after a lavish picnic by the river. Ethel accepts, fainting from joy before recovering to plan a grand society wedding at Westminster Abbey. Despite Salteena's brokenhearted tears at the ceremony, the wedding proceeds with immense pomp and magnificent refreshments.
Following their honeymoon in Egypt, the characters settle into married life with varying degrees of contentment. Bernard and Ethel raise a large family and remain deeply devoted to each other. Salteena eventually marries a palace maid and fathers ten children, though he occasionally regrets losing Ethel, while the Earl of Clincham encounters domestic turbulence with his own aristocratic wife.
