Jack and Algernon are wealthy gentlemen. Jack lives a respectable life in the country. Algernon lives in luxury in London and has invented an imaginary invalid friend whom he visits in the country. Jack has also invented a character, a younger brother called Ernest whom he uses as pretext for going up to London.
Jack wants to marry Algernon’s cousin Gwendolen, but must first convince her mother, Lady Bracknell, of the respectability of his parents. For Jack, having been abandoned in a handbag at Victoria station, this is quite a difficult task.
Algernon visits Jack’s house in the country and introduces himself to Cecily as Ernest, knowing that Cecily is already fascinated by tales of Ernest's wickedness. He further wins her over and they become engaged. Shortly after, Jack arrives home announcing Ernest’s death. Eventually, Jack discovers that his parents were Lady Bracknell’s sister and brother-in-law and that he is, in fact, Algernon’s older brother, called Ernest. The two sets of lovers are thus free to marry