Hiller Bernard Hill arrives at Paddington station in London with a boy Kieran O'Brien after a stay in Torquay, unaware that they’re being tailed by Ken Bones as they check into a nearby hotel. A few days pass, and the child is kidnapped by Gort, and Hiller himself is captured. The pair are taken to a derelict house where he encounters Salto. It becomes clear that Hiller is a computer programmer whom Salto has bribed to obtain details about the security system guarding a bank near Heathrow Airport. Salto is furious because he asked for documents, but Hiller only sent him a decipherable tape, a computer program that Salto cannot read. After this setback, Hiller hides with the boy and loses his job, and he discovers that the child is his wife’s son. When he finally returns home, he learns that the boy’s mother has left him.
Hiller and the Boy remain in captivity while he is coerced to decode the tape, threatened with violence. Once he succeeds, Salto gains the information he needs to plan the bank heist. Salto secures financing and brings in The Guv’nor to mastermind the operation, while The Bellman pinpointes the bank’s alarm system and anti-interference safeguards. Hiller explains how to bypass them and is recruited as the new Bellman. The gang sets their sights on performing the robbery just before Christmas, when the bank will hold more cash than usual.
On the night of the robbery, the crew deliberately triggers the alarm. The weary guards, hearing no true breach, assume it’s a false alarm, while the criminals seize a narrow window to slip inside. The Peterman coordinates access to the basement vault area, and the gang discovers that the vault door can be opened with a thermic lance. After cutting through, they haul away £13 million and release tear gas to disorient the guards, slipping away in a getaway car driven by The Wheelman. At a planned switch, they move from the car to a van, and during the journey they learn that the security guard dog handler has died. The Guv’nor grows anxious that they have violated a dangerous code by potentially harming others and worries that their identities will be exposed to the authorities. He rethinks the plan and guides the group toward the coast, traveling toward the beach near Dungeness Nuclear Power Station. Salto arrives later, bringing the boy.
On the beach, the Guv’nor tells Hiller that the boy and others will be flown abroad in a private plane while Hiller remains in the United Kingdom to undergo plastic surgery. In truth, the Guv’nor intends to kill Hiller, but the programmer fights back, seizing a pistol and fleeing into a nearby building where he had earlier constructed an Improvised Explosive Device using a propane cylinder. The blast explodes just as Hiller escapes, killing the Guv’nor and the others, while he escapes in the van with Salto driving. They reach the aeroplane pickup point, but Salto is wounded by a gunshot and dies in a pillbox. The plane intended to carry them does not land, and Hiller and the Boy drive to Heathrow Airport. They use the false passports meant for their getaway and board a flight to Rio de Janeiro, which is already booked for them.
On the plane, Hiller sits tense, fearing arrest when authorities board. It is revealed that the flight is secretly transporting human organs. The film ends with the aircraft taking off, leaving the fate of Hiller, the Boy, and their macabre cargo shrouded in uncertainty.
