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
Gwendolen gambles away all of her money, only to then find out that her family is financially ruined. Daniel meets Mirah when he saves her from trying to drown herself.
Act II
Gwendolen starts to go crazy with guilt over marrying Grandcourt. Daniel becomes thoroughly involved in finding Mirah's long-lost family. He meets Mordecai.
Act III
Grandcourt drowns. Daniel meets his real mother and finds out that he's Jewish. He proposes to Mirah. Gwendolen resolves to be a better person.