The main character of the movie is Travis Bickle, played by Robert De Niro. He is a former Marine and Vietnam War veteran who is struggling with insomnia and mental health issues. To cope, he takes a job as a taxi driver in New York City, where he is consumed by the sleaze and decay that he sees around him.
Travis becomes fixated on a young prostitute named Iris, played by Jodie Foster, whom he sees regularly on his nightly drives. He becomes convinced that she needs to be rescued from her life as a prostitute, and he begins to hatch a plan to save her.
As Travis's obsession with Iris grows, he becomes more and more unstable. He begins to carry a gun with him at all times, and he becomes convinced that he is a vigilante who can make a difference in the world.
The film is known for its gritty portrayal of New York City in the 1970s, as well as for its exploration of mental illness and the dark side of human nature. It was directed by Martin Scorsese and written by Paul Schrader, and it has gone on to become a classic of American cinema.