A wealthy heiress from New York, Milly Theale is young, pretty and without heirs to her fortune. She is also ill and concerned that her illness may indeed be fatal. She meets Susan Stringham, an older woman, who agrees to accompany Milly on a European tour. For Milly, it is important to live fully and to do so in a manner that brings pleasure to others. She is willing to assume the entire cost of Susan's trip and truly wants them both to enjoy themselves. After spending some time in the less populated areas of the Alps, Milly decides to travel to London. She want to be around the activity of a major city, where she can socialize more. As well, she wishes to look up Merton Densher, a young man from London, who she met in New York.