A local radio station in Norwich, North Norfolk Digital, has been bought out by a multinational conglomerate and is about to be re-branded as "Shape", with staff members facing redundancies. DJ Alan Partridge is unconcerned about the change but fellow DJ Pat Farrell (Colm Meaney) fears for his job, and pleads with Alan to gatecrash a board meeting and persuade the new owners not to get rid of him. When Alan inadvertently discovers it is either Pat or himself that must go, he betrays Pat, writing "JUST SACK PAT" on the meeting room flipchart. Pat is later asked to leave.That evening the new owners of the station host a party and while Alan is outside with his assistant Lynn (Felicity Montagu), Pat enters the station with a shotgun and holds the staff hostage. Alan returns to the party and is shot at by Pat. Escaping and commandeering a car he heads to the nearest police station (just over the road) to report events. The police press Alan into service as a negotiator, establish a command centre in a nearby school and send him back into the station to speak to Pat.Alan builds an uneasy rapport with Pat, who explains that he just wants his job back, and together with Alan's co-presenter Sidekick Simon (Tim Key) they continue to host an on-off radio show during the siege. Alan hallucinates several times about being a hero and ending the siege, but cannot bring himself to grab Pat's gun. As the siege becomes national news, Lynn is persuaded to ditch her frumpy style for a TV interview and Alan's ego swells due to his pivotal role. He steals a kiss from a co-worker named Angela who caught his eye earlier in the day (Monica Dolan).Alan accidentally locks himself out of the building and loses his trousers whilst trying to get back in through a window. The police realise he is ineffective as a negotiator and instead try to send in an undercover officer disguised as a pizza delivery man, but Alan interrupts and takes the pizzas in himself. Once inside, he discovers a taser in one of the boxes, and an argument erupts between the hostages during which the police burst in. Pat manages to escape with Alan and Alan's faithful Geordie friend Michael (Simon Greenall) in the stations tour bus. While on the tour bus Pat and Alan continue to host the ongoing radio show, and it seems as if they trust one another again. But when looking at a photo of the radio management, Pat notices Alan's "JUST SACK PAT" on the flipchart in the background, and recognising his handwriting deduces Alan was behind his redundancy. Alan hides in the tour bus portaloo and escapes under the bus in the septic tank.The final scene takes place on Cromer Pier where Pat faces off with Alan and the police. Michael tries to distract Pat by throwing himself off the pier (to no effect), and Pat explains he is depressed due to the death of his wife. Unable to shoot himself with the long-barreled shotgun, Pat gives the gun to Alan, who throws the weapon aside and is shot in the leg as it goes off, and also accidentally shot in the shoulder by a police sniper. Lynn arrives thinking Alan is dead but a paramedic assures him he will be fine.The film ends with Alan returning to North Norfolk Digital along with the (somewhat shell-shocked) Sidekick Simon and a weekly call-in from Pat who has now been jailed. Alan has also formed a relationship with mother-of-two Angela and is seen driving off on holiday with her and her two boys, towing a boat on a trailer bearing the legend "Alpha Papa".