An unstable ex-marine returns home from Vietnam, coping with depression and insomnia by taking a late night taxi driving gig in New York City and frequenting sleazy porn theaters. After witnessing the daunting lows of street life, his erratic thoughts turn violent and he develops intense delusions of grandeur, determined to right the social injustices he observes. He adopts an intense training regime, preparing to take on the lords of the night and saving a young prostitute in the process.
