Vietnam vet Travis Bickle is a loner in the mean streets of New York City, slipping slowly into isolation and violent misanthropy. In solving his insomnia by driving a yellow cab on the night shift, he grows increasingly disgusted by the low-lifes that hang out at night: "Someday a real rain will come and wash all the scum off the streets." His touching attempts to woo Betsy, a Senator's campaign worker, turn sour when he takes her to a porn movie on their first date. He even fails in his attempt to persuade child prostitute Iris to desert her pimp and return to her parents and school. Driven to the edge by powerlessness, he buys four handguns and sets out to solve all the problems that are troubling him.