In the year 1941, in the midst of World War II, in a city in western Morocco called "Casablanca", resides an upscale night-club called "Rick's Cafe Americain". This night club attracts a very electric clientele, from French, Italian, and Nazi officials, as well as refugees trying to buy passage to the United States, all in the melting-pot city of Casablanca, finding some small comfort in a night-club owned by one Rick Blaine. Rick, ever the cynical American expatriate, remains neutral in all matters, at least in the eyes of those who enter Rick's Cafe Americain.
The questions soon pour out; what makes Rick so cynical? How is he neutral if he has this persona? Do people trust him because of this, or do they judge him? Some of these questions are slowly strung together when Ugarte, a petty criminal, arrives at Rick's night-club and entrusts Rick with papers obtained from a murder of German couriers. These papers are highly valuable because they allow the owner to fly freely around Europe and eventually to America, something highly valuable to the refugees who inhabit the night-club most evenings. Ugarte is eventually killed by the police, but the papers remain in Rick's possession, the key to testing this neutrality of his.
What is the one thing that can usually shake someone's confidence? The unexpected arrival of an old flame. Enter Norwegian Ilsa Lund, ex-lover of Rick who he had every intention of marrying in another life in Paris. Ilsa's arrival also concludes that Rick still has love for her, yet learns that she is in fact married to Victor Laszlo, a fugitive Czech Resistance leader, who is hoping to make it to America with Ilsa.
Rick's cynicism evolves to bitterness as he ponders why Ilsa suddenly left him in Paris when they loved each other, with no word, and also how she came to be in Casablanca with this man as her husband. Ilsa however, is not the classic heart breaker as she is made out to be in Rick's mind. She learns of the papers in Rick's possession and steals into the cafe at night when it is closed and demands them from Rick, gun in hand.
Rick is convinced that Ilsa still loves him, as much as he loves her and she finally breaks down revealing the truth. That she does indeed still love him. She explains that while in Paris she learned that her husband had died in a concentration camp, and while making plans with Rick to leave occupied France together, she discovered that he was alive. Ilsa is torn on what to do as she has strong love for both men, and finally comes to an agreement with Rick that it would only be right if he still gave the papers to Laszlo, so he could continue his work.
Rick's neutrality is put to a final test when the time comes to let Laszlo go. Ilsa, who still loves both men is torn and finally has to be convinced by Rick to do what is right. Rick shoots down a policeman in the process of the escape, revealing who's side he really is on as well as joining fellow officer and friend Renault in the Free French at Brazzaville, coining one of the most recognizable phrases in film history; "Luis, I think this is the beginning of a beautiful friendship."
"Here's looking at you kid."