Harvey Keitel é Charlie, um homem que trabalha para crescer no submundo dos guetos de Little Italy, em Nova York. Ao seu lado, porém, está Johnny Boy (De Niro, em sua primeira parceria com Scorsese), um jovem revoltado, agressivo e sem escrúpulos, que vive se metendo em confusões por causa de dívidas de jogo. Caminhos Perigosos retrata o cotidiano desses dois indivíduos, em meio à realidade violenta do subúrbio das grandes cidades. O filme é um retrato visceral do ambiente em que crescera o diretor Martin Scorsese, cuja infância vivera no mesmo bairro nova-yorkino em que se passa a obra.
"Boxcar" Bertha Thompson, a transient woman in Arkansas during the violence-filled Depression of the early '30s, meets up with rabble-rousing union man "Big" Bill Shelly and the two team up to fight the corrupt railroad establishment.
A policeman is accused of manslaughtering a 14-year-old boy but is acquitted of all charges. Still, he feels a lot of guilt and begins to doubt if he really is innocent after all.
A young woman's suicide attempt is stopped by an old man passing by. The two fall in love -- but the relationship between the young girl and old man is threatened when a blackmailer from her past shows up.
Gerald Meek and Myrna McAllister go to city hall to apply for a marriage license. Gerald wanders into the Marine Recruiting office by mistake and Sergeant Delaney signs him into the Marine Corps and sends him for a medical examination before Gerald realizes what has happened. He finds himself in uniform and ready to be shipped to boot camp without any delay, other than explain to his intended-bride that Uncle Sam has other plans for him.
A photographer is choked to death just outside of where a college dance is being held. The body is discovered by Lee Watson, but promptly disappears, as it is being whisked from one point to another on the campus by a night watchman, who is an ex-convict.
