"2001" is a story of evolution. Sometime in the distant past, someone or something nudged evolution by placing a monolith on Earth (presumably elsewhere throughout the universe as well). Evolution then enabled humankind to reach the moon's surface, where yet another monolith is found, one that signals the monolith placers that humankind has evolved that far. Now a race begins between computers (HAL) and human (Bowman) to reach the monolith placers. The winner will achieve the next step in evolution, whatever that may be.
Travis Bickle is an ex-Marine and Vietnam War veteran living in New York City. As he suffers from insomnia, he spends his time working as a taxi driver at night, watching porn movies at seedy cinemas during the day, or thinking about how the world, New York in particular, has deteriorated into a cesspool. He's a loner who has strong opinions about what is right and wrong with mankind. For him, the one bright spot in New York humanity is Betsy, a worker on the presidential nomination campaign of Senator Charles Palantine. He becomes obsessed with her. After an incident with her, he believes he has to do whatever he needs to make the world a better place in his opinion. One of his priorities is to be the savior for Iris, a twelve-year-old runaway and prostitute who he believes wants out of the profession and under the thumb of her pimp and lover Matthew.
Due to his knowledge of the native Bedouin tribes, British Lieutenant TE. Lawrence is sent to Arabia to find Prince Faisal and serve as a liaison between the Arabs and the British in their fight against the Turks. With the aid of native Sherif Ali, Lawrence rebels against the orders of his superior officer and strikes out on a daring camel journey across the harsh desert to attack a well-guarded Turkish port.
John "Scottie" Ferguson is a retired San Francisco police detective who suffers from acrophobia and Madeleine is the lady who leads him to high places. A wealthy shipbuilder who is an acquaintance from college days approaches Scottie and asks him to follow his beautiful wife, Madeleine. He fears she is going insane, maybe even contemplating suicide, he believes she is possessed by a dead ancestor. Scottie is skeptical, but agrees after he sees the beautiful Madeleine.
When two Chicago musicians, Joe and Jerry, witness the the St. Valentine's Day massacre, they want to get out of town and get away from the gangster responsible, Spats Colombo. They're desperate to get a gig out of town but the only job they know of is in an all-girl band heading to Florida. They show up at the train station as Josephine and Daphne, the replacement saxophone and bass players. They certainly enjoy being around the girls, especially Sugar Kane Kowalczyk who sings and plays the ukulele. Joe in particular sets out to woo her while Jerry/Daphne is wooed by a millionaire, Osgood Fielding III. Mayhem ensues as the two men try to keep their true identities hidden and Spats Colombo and his crew show up for a meeting with several other crime lords.