Casablanca

Rick Blaine (Humphrey Bogart) is a bitter, cynical American expatriate in Casablanca. He owns and runs "Rick's Café Américain", an upscale nightclub and gambling den that attracts a mixed clientèle of Vichy French and Nazi officials, refugees and thieves. Although Rick professes to be neutral in all matters, it is later revealed that he had run guns to Ethiopia to combat the 1935 Italian invasion, and fought on the Republican side in the Spanish Civil War against Francisco Franco's Nationalists.

Ugarte (Peter Lorre), a petty criminal, arrives in Rick's club with "letters of transit" obtained through the murder of two German couriers. The papers allow the bearer to travel freely around German-controlled Europe and to neutral Portugal, and from there to America. The letters are almost priceless to any of the continual stream of refugees who end up stranded in Casablanca. Ugarte plans to make his fortune by selling them to the highest bidder, who is due to arrive at the club later that night. However, before the exchange can take place, Ugarte is arrested by the local police, under the command of Captain Louis Renault (Claude Rains), a corrupt opportunist who later says of himself, "I have no convictions ... I blow with the wind, and the prevailing wind happens to be from Vichy." Unbeknownst to Renault and the Nazis, Ugarte had entrusted the letters to Rick because "... somehow, just because you despise me, you are the only one I trust." (Ugarte dies in police custody without revealing the location of the letters.)
At this point, the reason for Rick's bitterness re-enters his life. His ex-lover Ilsa Lund (Ingrid Bergman) arrives with her husband, Victor Laszlo (Paul Henreid), a fugitive Czech Resistance leader long sought by the Nazis. The couple need the letters to leave Casablanca for America to continue his work. German Major Strasser (Conrad Veidt) arrives to ensure that Laszlo does not succeed.

When Laszlo speaks with Signor Ferrari (Sydney Greenstreet), a major figure in the criminal underworld and Rick's business rival, Ferrari divulges his suspicion that Rick has the letters. Laszlo meets with Rick privately, but Rick refuses to part with the documents, telling Laszlo to ask his wife for the reason. They are interrupted when a group of Nazi officers led by Strasser begins to sing "Die Wacht am Rhein", a German patriotic song. In response, Laszlo orders the house band to play "La Marseillais", the French national anthem. The band looks to Rick for permission, and he nods his head. Laszlo starts singing, alone at first, then long-suppressed patriotic fervor grips the crowd and everyone joins in, drowning out the Germans. In retaliation, Strasser orders Renault to close the club.

That night, Ilsa confronts Rick in the deserted cafe. When he refuses to give her the letters, she threatens him with a gun, but is unable to shoot, confessing that she still loves him. She explains that when she first met and fell in love with him in Paris, she believed that her husband had been killed trying to escape from a Nazi concentration camp. Later, with the German army on the verge of capturing the city, she learned that Laszlo was in fact alive and in hiding. She left Rick without explanation to tend to an ill Laszlo.

With the revelation, Rick's bitterness dissolves and the lovers are reconciled. Rick agrees to help, leading her to believe that she will stay behind with him when Laszlo leaves. When Laszlo unexpectedly shows up, after having narrowly escaped a police raid on a Resistance meeting, Rick has waiter Carl (S. Z. Sakall) secretly take Ilsa back to the hotel while the two men talk.
Laszlo reveals that he is aware of Rick's love for Ilsa and tries to get Rick to use the letters to take her to safety. However, the police arrive and arrest Laszlo on a petty charge. Rick convinces Renault to release Laszlo by promising to set him up for a much more serious crime: possession of the letters of transit. To allay Renault's suspicions about his motives, Rick explains that he and Ilsa will be leaving for America.

However, when Renault tries to arrest Laszlo, Rick double crosses Renault, forcing him at gunpoint to assist in their escape. At the last moment, Rick makes Ilsa board the plane to Lisbon with her husband, telling her that she would regret it if she stayed, "Maybe not today, maybe not tomorrow, but soon and for the rest of your life."

Major Strasser drives up by himself, having been tipped off by Renault, but Rick shoots him when he tries to intervene. When police reinforcements arrive, Renault pauses, then tells his men to "Round up the usual suspects." Once they are alone, Renault suggests to Rick that they leave Casablanca and join the Free French at Brazzaville. They walk off into the fog with one of the most memorable exit lines in movie history: "Louis, I think this is the beginning of a beautiful friendship.

"As Time Goes By" Dooley Wilson