On October 6, 1970 while boarding an international flight out of Istanbul Airport, American Billy Hayes (Brad Davis) is caught attempting to smuggle two kilos of hashish out of the country, the drugs strapped to his body. He is told that he will be released if he cooperates with the authorities in identifying the person who sold him the hashish. Billy's troubles really begin when after that assistance, he makes a run for it and is recaptured. He is initially sentenced to just over four years for possession, with no time for the more harsh crime of smuggling. The prison environment is inhospitable in every sense, with a sadistic prison guard named Hamidou (Paul L. Smith) ruling the prison, he who relishes the mental and physical torture he inflicts on the prisoners for whatever reason. Told to trust no one, Billy does befriend a few of the other inmates, namely fellow American Jimmy Booth (Randy Quaid) (in for stealing two candlesticks from a mosque), a Swede named Erich (Norbert Weisser), and one of the senior prisoners having already served seven years, an Englishman named Max (Sir John Hurt), the latter two also in for hashish-related charges. One prisoner not befriended is Rifki (Paolo Bonacelli), who wields power in the prison as the unofficial eyes and ears for the guards. As Billy, his family and his girlfriend Susan (Irene Miracle) attempt through legal and diplomatic channels for Billy's release, Max tells him that the only way out is to "catch the midnight express" (escape), which is what Jimmy is continually trying to do. When Billy's situation changes, he becomes more desperate in every sense of the word. It seems as if Billy has only two options: to let the prison ultimately figuratively then literally kill him, or to somehow regain control of his life through whatever means available.