Ugarte murders the German couriers to obtain the valuable letters of transit, which he plans to sell to Laszlo for a considerable fee.
Louis approaches everything with wit, and many of the film's best lines are his.
At the beginning of the movie, Yvonne is Rick's neglected, miserable lover.
In a flashback, we see Rick in Paris.
Laszlo and Berger are able to discuss such a sale during her performance.
Despite her obvious commitment to her husband and her confessions of love to Rick both in Paris and later in Casablanca, she rarely displays much passion.