The fourth episode of BBC One's "Nightsleeper" ratchets up the tension as the high-stakes game of cat and mouse between the passengers and the unseen hackers continues. With the train still under the control of the enigmatic "Blue Blockade Group" (BBG) and the authorities' attempts to regain control proving futile, Abby Aysgarth and Joe Roag must navigate a treacherous path to uncover the truth behind the hijacking.
The episode opens with the aftermath of the tragic death of Oil Rig Man, whose baby is now born without a father. Joe, still reeling from the loss, discovers a USB stick that could hold the key to understanding the hackers' motives. As the NCSC scrambles to make sense of the situation, Abby becomes increasingly suspicious of the Director General, Nicola Miller, who seems to be withholding crucial information.
The plot thickens as Abby and her team at the NCSC uncover a second phone jammer on the train, suggesting that there may be a traitor in their midst. This revelation sends Joe into a spiral of doubt as he questions the loyalty of his fellow passengers. The discovery of a second satellite phone and the realization that someone on the train is communicating with the hackers in real-time adds a new layer of complexity to the already tangled web of intrigue.
As the train hurtles towards its unknown fate, Abby hatches a daring plan to divert the train onto a separate line, buying precious time for her team to crack the hackers' code. However, her plan is met with resistance from the Director General, who orders a military strike on the train in a desperate attempt to stop it by force. This decision leads to a dramatic confrontation between Abby and the authorities, as she struggles to balance the need for action with the imperative to protect the lives of the passengers.
Meanwhile, Joe faces his own challenges aboard the train. As the passengers turn on each other in the wake of the Oil Rig Man's death, Joe must rally them together to face the common threat. His leadership is tested as he confronts the possibility that one of them may be working with the hackers. The tension aboard the train reaches a boiling point when bullets fly through the window, causing a fire that threatens to consume the train.
In a dramatic twist, Abby discovers that the code used in the attack was written by her, during her misspent youth as a rogue hacker. This revelation shakes her to the core, as she grapples with the knowledge that her own genius has been weaponized against her. As she confronts the Director General about the true nature of the operation, she is met with a chilling accusation: the code used in the attack was written by Abby herself.
The episode concludes with a shocking revelation: there is an unidentified male on the train, someone that the other passengers are unaware of. This discovery sends Abby and Joe into a race against time to uncover the identity of this mysterious figure and determine his role in the hijacking.
"Nightsleeper" continues to deliver on its promise of a thrilling, real-time drama that keeps viewers guessing until the very end. The fourth episode is a masterclass in suspense, with each scene carefully crafted to maintain the tension and keep the audience on the edge of their seats. The performances are compelling, particularly Roach's portrayal of Abby, which adds a layer of vulnerability to her otherwise steely exterior. As the series progresses, viewers can expect more twists, turns, and a race against time that will leave them breathless.