Travis Bickle is an outsider. Not least because of his job as a cab driver, the Vietnam veteran learns to hate society. The emptiness and coldness that seems to emanate from the people around him leads him to get himself weapons and arm himself for the fight against the rest of the world. Almost by chance, he chooses a young prostitute and takes her on. His goal is to free her from her suffering. When he finally realizes that she doesn't even seem to realize the circumstances under which she lives, he runs amok...