Following the
self-immolation of a steelworker, whose son recently died in an industrial accident at the
Port Talbot steelworks, tensions are running high between the workforce of Port Talbot steelworks and its new foreign owners over fears of a surreptitious closure. Geoff Driscoll, a
trade union steward haunted by memories of his father, who committed suicide following the failure of the
1984 miners' strike, attempts to come to an agreement with management that quells anger amongst the workforce but his efforts are undermined by a broken promise from the management. The workers, inspired by reports of the mythical "red monk" and speeches by Geoff's estranged wife, Dee, hold a successful strike ballot and begin a blockade of the steelworks. Geoff and Dee's children, Owen and Thea, have fallen out after Thea arrested Owen to protect him from drug dealers. Thea and Dee attempt to celebrate the birthday of Thea's young son Rhys, whose father Dan has been forced to seek employment in Germany. Owen attempts to win the affections of Anna, a young Polish immigrant he met online, while seeking a purpose to his life in joining the industrial action. Over the following days, as footage of Dee Driscoll's impassioned speeches on the picket line go viral, demonstrations by various political groups begin across Wales which lead the British government to crack down on the growing civil disobedience, putting Thea and the rest of her family on opposing sides as the local police unite with Gordius, a private security contractor hired by the government to protect
agency workers brought into the steelworks. Matters come to a head after troops are deployed to keep order in Port Talbot and telecommunications are shut off. A protest march breaks into a riot after Owen throws a metal pole at police lines. In the aftermath Owen is held at a local makeshift detention facility, while Wales is effectively put under martial law and sealed off from the rest of the country. The family, fearing for their safety after Thea sees Owen highlighted in a Gordius database, break Owen out from the facility with help from Anna and go on the run, hoping to escape the growing violence. The family however are unable to pick up Rhys (who Thea had left with Dan's parents during the disorder) before the authorities are made aware of the breakout, forcing Thea to ask Dan's father Philip to bring Rhys to them. In the growing confusion, while trying to evade an army checkpoint, Philip and Rhys board a lorry smuggling Welsh refugees into England. With no choice but to follow, Dan arranges for the family to make their way to
Cheltenham to hopefully meet up with Rhys and Philip. The main group are smuggled across the border by a sympathetic vicar, avoiding anti-Welsh vigilante blockades by masquerading as dead soldiers. Upon arrival however the group find they have been blamed for the violence that has taken hold in Wales and are forced to flee the town after the arrival of "The Welsh Catcher", a mercenary named Hogwood who has been contracted to hunt down Welsh people who've crossed into England. Heading into the countryside, the group take refuge with Dee's estranged sister Elaine and her
Freemason husband Hector, where they are joined by Rhys and Philip. Unable to safely stay in England or return to Wales the group are given Hector's canalboat in a bid to make it to the coast to join other Welsh people hoping to be smuggled across the
Channel while Philip, revealed to also be a Freemason and wanting to return to his ill wife, is ferried by Hector and others back to Wales. Arriving at the coast the group find shelter at a makeshift refugee camp, though they are soon discovered by Hogwood (who is revealed to be Welsh himself) and other mercenaries. Geoff attempts to convince Hogwood of their innocence and to let them go. Hogwood, while admitting that he knows the decision over who he's to target was made by an unaccountable
black-box algorithmic system, says he'll follow his instructions nonetheless. He gives the camp an ultimatum: hand over Owen or be razed to the ground. Following discussion within the camp the family are allowed to flee, making their way to the smugglers, while the other occupants of the camp perform a distraction. On the beach Owen decides to stay and try to return to Port Talbot with Anna in tow, while the rest of his family board a small boat to France. While crossing the Channel the boat begins to take on water. Geoff, having made peace with his father's death and feeling guilt over having secretly been the "red monk" that inspired the strike, sacrifices himself by jumping overboard. Despite surviving the passage, the others, along with Dan who had been waiting for them, are detained by armed French police to an unknown fate. In Wales, Owen and Anna successfully make their way back to Port Talbot whereupon Owen tosses an ancient sword his father had carried along their journey into the sea. ==Cast and characters==