Nighttime in Manchester. DI Harry Martineau and his young colleague, DC Devery, discuss the possibility of escaped convict Don Starling returning to his old haunts to take revenge on Martineau, who Starling blames for his ten-year sentence. Martineau and Devery visit The Lacey Arms, run by Doug Savage. Barmaid 'Lucky' Luske receives a call from Starling, a former boyfriend, instructing her not to reveal his whereabouts.

Starling breaks into Laurie Lovatt's snooker hall and reveals his new heist plans to Lovatt. Martineau returns home to find his wife angry that he had not come home to dinner. When Martineau suggests they become a proper family and have children, the two row bitterly.

The following morning, bookmaker Gus Hawkins and his wife set off for the Doncaster races. Hawkins dispatches Sam and Cecily, his young clerks, to bank the previous day's takings. However, the pair are trailed by Lovatt's gang and overpowered. Sam is left unconscious in the gutter, while Cecily, chained to the money, is abducted in the gang's Buick. To stifle her screams, Starling coshes her to death, dumping her corpse by the side of the moorland road. A passing motorist, forced off the road by the gang, discovers the body and alerts the police. Martineau notices that the dead girl's fingers are covered in 'malachite green' - a chemical used to trace stolen bank notes.

The gang abandon the Buick and are picked up by a black taxi. Martineau learns that the bank notes were stolen and that the thief had been gambling at the Doncaster races. Martineau concludes that Starling, now wanted for the murder of a prison guard during his escape, is behind the robbery. Martineau and Starling have known each other since childhood. Starling makes his way to Hawkins' villa; Hawkins' wife, Chloe, is another former girlfriend. Chloe hides Starling in the attic but the following morning Hawkins enters the attic to investigate noises. Starling knocks him unconscious, then brutally attacks Chloe.

After visiting Hawkins in hospital, Martineau interrogates Chloe and learns that she was hiding Starling in the attic. Later, an illegal 'pitch & toss' gambling school, organised by Savage and Bert Darwin, takes place on the moors. Tawney Jakes attempts to gamble some of his robbery proceeds, but is prevented by Lovatt and Roach. Just then, the game is interrupted by a fleet of police cars. Savage surrenders, and reluctantly supplies Martineau with a list of gambling school members, including Jakes and Roach. Martineau visits Lovatt's garage and discovers some of the bank notes hidden in a car engine. Martineau then arrests Lovatt and, after threatening to frame his innocent brother, Lovatt names Tawny Jakes. Jakes attempts to flee by rail but is caught. Under duress, Jakes implicates Starling in the murder of Cecily Wainwright.

On the lookout for Starling, Devery visits the warehouse of Furnisher Steele, whose deaf-mute granddaughter Silver seems to be taken with the young policeman. That night, Starling takes refuge in Steele's property and threatens the old man with reprisals against Silver. In the morning Martineau visits Lucky Luske. The Inspector and the barmaid are clearly attracted to one another but Martineau reminds Lucky that he is married.

Starling, by now very unbalanced, injures Silver as she attempts to seek help, and climbs to the warehouse roof toting a gun. Martineau is shot at, but is still able to fight with Starling, forced him over the parapet. Martineau rescues him.

Several weeks later, Starling is hanged. Martineau, at home on sick leave, is distraught. He pours himself a large drink and bellows at his concerned wife that he is 'on edge', then leaves the house, promising to return soon and to moderate his moods. Walking, Martineau encounters Lucky, who expresses her wish for a good father for her children. Before her bus departs, Martineau makes her promise to name one of her future offspring 'Harry'. Devery pulls up, Devery explains that he did not visit Martineau in hospital because of Harry's promotion to DCI - the gulf in their ranks is vast. Martineau understands his reasoning. Devery offers Martineau a lift, but he refuses, saying that this is his last night of freedom. Harry walks alone through the streets of Manchester.