For a three-act plot analysis, put on your screenwriter’s hat. Moviemakers know the formula well: at the end of Act One, the main character is drawn in completely to a conflict. During Act Two, she is farthest away from her goals. At the end of Act Three, the story is resolved.
Act I
After Isabel Archer makes her appearance in England, Ralph convinces Mr. Touchett to leave the newly discovered cousin a large inheritance.
Act II
Isabel marries Osmond after Madame Merle introduces them. After two years of marriage, she is miserable and isolated from her friends and family.
Act III
Isabel breaks with Osmond, and decides to leave Rome for England, where Ralph is dying. Before she leaves, she visits Pansy at the convent. Isabel is faced with the choice to return to Osmond or flee with Caspar Goodwood.