Prisoner (British TV series)

Harrison Dempsey, the leader of organised crime group Pegasus, stands trial at the Old Bailey after being arrested by the National Crime Unit. Tibor Stone, a former hitman, agrees to testify against Dempsey in exchange for witness protection and a reduced sentence. On discovering his safehouse in St Davids may be compromised, NCU official Alex Tebbit requisitions a nearby prisoner transport van manned by Amber Todd and her colleague Joe Sutherland to transport Tabor to London overnight with an AFO escort. Tibor, a diabetic, needs to be given insulin regularly. The convoy is attacked in Cardiff by a drone and gunmen led by Nina, hired by Dempsey’s son Declan. Joe and the AFO’s are killed while Amber handcuffs herself to Tibor and the two escape. Amber treats Tibor’s wounds and gives him a Glucagon shot. He explains that Nina is his former protégé. Amber calls the NCU to arrange evacuation, and Tebbit warns her about Tibor. The two appear to be extracted by the NCU, but Tibor realizes Nina is a passenger in the car.

Nina takes Tibor and Amber to a warehouse 3D printing weapons, implying she has a mole in the NCU. Declan, involved with Nina, arrives with Miles, his father’s lieutenant, seeking instructions on how to proceed. NCU Director Campbell focuses on finding the mole. NCU agent Will O’Neill warns Amber’s husband Olly not to return home with their baby, Mia. Tibor lies to Amber about having a son killed by Pegasus to manipulate her. On a call with Dempsey, Tibor says Declan is the reason they both got caught, and he plans to destroy their lives how Declan destroyed his. Dempsey instructs Nina to kill Amber. Using a teaspoon, Tibor escapes with Amber in Declan’s Rolls Royce. Olly and Mia are targeted, but Tibor guides him on how to escape and gives him an address. The NCU discovers the drone weapons are advanced 3D printed alloy. Campbell suspends Tebbit, believing he is the mole, but doesn’t have enough to arrest him. Tibor robs a chop shop for cash to get him and Amber to London, and threatens her to comply.

Tibor and Amber get Nina arrested by the police, and pay a trucker to drive them to London. O’Neill, now leading the investigation, is shown to be the NCU mole, and redirects focus to Amber. Dempsey forces him to get Nina released. Tebbit links Pegasus associate Ivanov to the polymer in the drone weapons. He warns Amber’s colleagues O’Neill plans to set her up. When O’Neill interviews them, they steal his phone and download the contents. Olly and Mia arrive at the address, and are taken in by Carla Dumont, Tibor’s mother. On discovering an urn, she tells Olly that she and Tibor killed his violent father. Miles offers the polymer weapons to Russian criminal Mikhail, assuring him the sale will happen when Dempsey is acquitted. However, the impulsive Declan kills Miles and assumes control of the deal. The trucker gives Tibor and Amber up to Declan for more money, but they lock him in the back and escape. Nina frees him, and suggests they set up their own enterprise after the Mikhail deal and killing Stone.

When Tibor goes into hypoglycemic shock, Amber steals a car and drives them to Carla’s house, reuniting with Olly and Mia. Carla revives Tibor (addressing him by his real name, Étienne) and Olly cuts the handcuffs with boltcutters. Concerned by Tibor and Carla’s behaviour, Olly urges Amber to leave. However, Amber still wants to get Tibor to court, knowing their pursuers won’t stop otherwise. Desperate, Olly calls O’Neill and gives him the postcode, which he passes to Declan instead of the NCU. Amber, Tibor and Carla probe each other psychologically about their personalities and traumatic backgrounds, including Amber's mother being in prison and Carla encouraging Tibor to kill people from a young age. Nina and her men attack the property, but Carla and Tibor kill several and Amber injures one with a nail gun. Carla is shot in the stomach by Nina, and asks Tibor to euthanise her, which is witnessed by Amber. Nina confronts Olly and incapacitates him, taking Mia and driving away as Amber pursues on foot.

After dropping Olly at hospital, Tibor offers to exchange himself for Mia. Amber calls her colleagues and Tebbit, who prioritises getting Tibor to court over recovering Mia. He also believes Pegasus are assisting a coordinated terror attack in six countries dubbed the “Day of Action” by selling the weapons. Tebbit gives Campbell a USB drive with proof of O’Neill’s treachery and the upcoming attack, but she hands him to Pegasus who kill him, making it look like suicide. Tibor and Amber force O’Neill to arrange the handover and get her mother Kelly temporarily released from prison. Kelly connects them with her criminal associates to rescue her Mia and extract Tibor. The exchange takes place at an ice hockey rink owned by Kelly’s friend, but Nina’s team bypasses security with the polymer weapons. O’Neill is killed rescuing Mia from Nina, and Kelly prepares to take Mia to Olly. Amber fights Nina, who gets away, and helps Tibor escape. However, she is arrested by armed police after picking up Tibor's gun.

Amber gets Campbell to release her so she can get Stone to court before the trial concludes. Knowing her Pegasus affiliation, Amber disposes of a tracker Campbell placed on her, and she and her colleagues Marcus and Jade use three identical prison vans to avoid Nina and get Tibor to court. Her colleagues Jamal and Phil give NCU agent Nancy Howard, a friend of Tebbit, the intel on the “Day of Action” and warn her of Campbell’s affiliation. In a surprise move, Tibor denies knowing Dempsey on the stand, resulting in his acquittal. Dempsey completes the weapons sale. Howard forces Campbell to tell Home Secretary Viraj Mundhra, about the weapons deal. Campbell claims she kept it secret due to the trial sensitivity. Mundhra believes her, but the pressure forces her to seize the UK gun shipment against Dempsey’s orders. Nina and Declan secretly re-route the EU shipment. Tibor escapes custody and directs Amber to Dempsey’s mansion, claiming they would both still be unsafe if he was in prison. She doesn't object when he kills Mikhail, Declan and Dempsey. Amber and Tibor part ways. However, Nina gets the drop on Tibor and kills him, wanting revenge for the death of Declan. Whilst driving to reunite with Olly and Mia, Amber appears to remember that Nina is still at large.