As the curtains rise on this installment of Shetland, we are greeted by a poignant flashback depicting John Harris (Vincent Regan), accompanied by a youthful Fergus. With a gentle yet resolute tone, John informs Fergus that the boat will eventually be theirs—a shared inheritance for him and his brother. Switching to the present day, we find John engaged in work with the grown-up Fergus (Macleod Stephen). Meanwhile, Patrick (Ross Anderson) reaches out to Archie, pleading for his help. Suddenly, a cloud of anxiety envelops John as he realizes Fergus is no longer breathing.
DI Ruth Calder (Ashley Jensen) and DI Alison 'Tosh' McIntosh (Alison O'Donnell) arrive on the scene just in time. Patrick, distressed, reveals that John is refusing to let anyone near Fergus. Tosh attempts to persuade John to step away from his fallen companion, while Ruth firmly informs Patrick that he must remain off the boat, now designated as a crime scene. She endeavors to calm his frayed nerves, but Patrick is consumed with guilt, confessing that he and John were in a heated argument, with Fergus caught in the middle. Their dispute centered on Annie. Ruth postpones further discussion on the subject, instead inquiring about Patrick's whereabouts on Friday night.
Patrick admits to a break-in at the Bett House, driven by rumors that Ian stored large amounts of cash for his business—money Patrick owed to JJ. He insists that the house was empty of cash, a fact JJ can attest to. Though he regarded Annie with disdain, Patrick emphatically denies any involvement in her demise. Ruth informs him of his impending trip to the station for an interview, followed by detention and the possibility of a trial.
John is escorted to a cell, where Tosh delivers the harsh reality: he won't see Fergus again until after the post-mortem examination. Sgt Billy McCabe (Lewis Howden) provides Tosh with crucial information regarding the flights mentioned by Jamie. Tosh entrusts McCabe with the task of offering John a tea and keeping a watchful eye on him, if he gets a moment's respite.
Elsewhere, Karin Jakobson (Nathalie Merchant) gently reminds Stefan Jakobson (Johannes Lassen) of his absence from their bed the previous night. Stefan explains that he slept in the guest room due to Astrid's restless night. Karin expresses her desire to avoid conflict but emphasizes the risks involved for Astrid, their relationship, and their company. Stefan queries if her concerns stem from financial worries, but Karin reveals her deeper fear—the future of their family. Stefan confesses that Astrid (Ines Hoysaeter Asserson) is his sole priority. Rushing to her room to check on her, he discovers that Astrid is missing. Karin urges him to call the police, but Stefan insists on finding her himself, fearing the repercussions of police involvement.
Astrid, meanwhile, spots a vehicle and instinctively seeks cover. Elsewhere, Ruth engages in conversation with Harry Lamont (Tibu Fortes) and Sandy Wilson (Steven Robertson) about the marine facility. Tosh joins them, and Sandy reveals that the marine lab is funded by PharmaRes, a company that has been chartering incoming flights. However, Harry remains steadfast, refusing to authorize a search unless concrete evidence of criminal activity is presented.
Elsewhere, Lisa (Tara Lee) and Angus (Jimmy Yuill) find themselves in the company of Reverend Alan Calder (Steven Miller). During their conversation with Angus, he rants about the shadowy depths of the state, while Angus himself is given Paracetamol, hinting at an underlying discomfort.
Ruth inquiries about Anton Bergen's assertions to him, revealing that Anton had claimed they indulged in sinister activities within the confines of the research lab. Anton had reached out to him via the website 'Shetland Confidential,' a platform rife with Angus's conspiracy theories. Angus, convinced of his own rightness after gaining entry, struggles to recall the specifics of what he witnessed. He recounts being assaulted and awakening in a medical facility. Privately, Ruth expresses her discontent to Alan for allowing them to reside in the house. Tosh informs Ruth that Harris is securing a search warrant for their investigation. Meanwhile, Stefan remains unsuccessful in locating or contacting Astrid. He spots a figure strolling down the road but to his disappointment, it's not her.
Dr. Devinda Mohan, played by Bridgitta Roy, enters the lab and receives a call from a nearby desk phone just as Ruth and Tosh arrive to conduct their search. Ruth ponders the location of the experiments, her attention drawn to a missing door cleverly concealed. They seek Lorna's assistance in shifting a cabinet to uncover a hidden room, inside which they discover a menacing chair. Ruth insists they bring Cora to this room.
In an interview room, Dr. Mohan refuses to divulge any information to Ruth, who probes her about Anton Bergen and Annie Bett. Mohan remains silent, prompting Tosh to halt the interview upon receiving a call from Cora. Cora McLean, portrayed by Anne Kidd, reveals to Tosh that Mohan has been working with stem cells, requiring a license for such use. Cora suspects she has been developing a customized treatment, possibly for a single affluent patient, prompting Ruth to consider Astrid as the potential recipient.
Returning to confront Mohan, Ruth accuses her of treating Astrid with stem cells derived from human embryos, asserting the treatment is unlicensed and potentially unlawful. Following the interview, Ruth and Tosh discuss Mohan's involvement in developing a treatment for Astrid, which explains Anton Bergen's presence at the lab on the night of his and Annie's demise. Bergen had intended to halt the treatment. Mohan alleges that Stefan left the lab to confront Bergen and did not return for an hour.
Nathan Huang, played by Marlowe Chan-Reeves, opens the door to find Astrid standing outside. Upon letting her in, Astrid pleas for his help, unaware of Anton's fate and eager to leave Shetland undetected. She reveals Anton's affection for Nathan and their plans to leave together. Ruth and Tosh visit Karin, who inquires about Astrid's whereabouts. Tosh informs Billy of Astrid's disappearance, while Ruth searches her room and discovers her missing passport. Karin, despite being Astrid's stepmother, insists on her innocence, noting that Stefan has made it clear that Astrid is his responsibility. Karin occasionally wonders if the treatment does more harm than good but doubts Stefan's involvement in the deaths.
Billy dials Tosh's number, urgency lacing his voice as he informs her that Astrid has secured a seat on a flight bound from Sumburgh to Edinburgh. Tosh, keen on action, demands deployment of units at the airport and organizes a search party to comb through the Jakobson residence. Karin, puzzled, reveals she has no connections in Edinburgh and hasn't laid eyes on her birth mother, Esther, for ages, adding that if reunion was on her mind, Tallinn would be her destination.
Outside, beneath the open sky, Tosh and Ruth engage in a hushed conversation, pondering if Anton's ultimate goal was to reunite Astrid with her mother. Karin, meantime, places a message on Stefan's voicemail, alerting him to the police involvement. Ian Bett, portrayed by Robert Jack, pays Noah, portrayed by Jacob Ferguson, a visit, while Noreen Stack, warmly embodied by Lesley Hart, greets Ian back home. Euan Rossi, played by Ian Hart, keeps a discreet watch from afar.
At the airport, Tosh and her team conduct a thorough sweep, leaving no stone unturned. Nathan, on the other hand, engages Joe in discussions about delivering items to his cousin's eatery in Aberdeen. Joe directs Nathan to the drop-off point and processes his paperwork. Unbeknownst to them, Astrid slips into the truck and conceals herself, initiating a chain of escalating tensions.
Sandy's sharp eyes spot Stefan, leading to his prompt arrest on murder suspicions. Inside the truck, Astrid's panic reaches a crescendo; she pounds frantically on the sides, her distress echoing through the confined space. Nathan's phone buzzes with a call from Astrid's device. His return call goes unanswered, and despite attempts to reach Joe, who is conveniently out of earshot, Nathan eventually seeks assistance from the Shetland Police.
Billy's follow-up call to Tosh reveals Astrid's unexpected destination. Tosh and Ruth spring into action, their race against time culminating in the discovery of Astrid, unconscious, in the truck's rear compartment. Elsewhere, Alan informs Michael Stack, portrayed by Andrew John Tait, of his intent to collect Lisa's belongings, and they share poignant thoughts about holding a memorial for Annie.
Euan Rossi approaches Noah, introducing himself as a friend of his late mother's. Ian's emergence prompts Euan to hastily retreat, his demeanor turning rough as he vows to avoid conflict. Claiming to rectify past wrongs, Euan brushes off Ian's queries with evasive answers.
In the hospital setting, Ruth and Tosh gently probe Astrid about Anton. Recalling a day she collapsed, Astrid reveals Anton's compassionate offer to aid her escape from Shetland. Through a friend, Anton arranged passage to Estonia for Astrid, mentioning a mysterious Annie Bett, though they never met. Stefan, having found Tallinn maps on Astrid's phone, extracted details from her under duress. Astrid swears she didn't witness Annie or Anton at the lab that fateful night, recalling Stefan's tearful return an hour after his initial departure. She insists Stefan is incapable of harming Anton.
Tosh and Ruth cross-examine Harry regarding Stefan, who in turn requests a conversation with them. When questioned about stem cell therapy, Stefan admits contemplation spurred by his daughter's plight, believing in Mohan's method's efficacy. He accuses Anton of manipulating Astrid and confesses to a physical altercation with Anton that night but claims ignorance about Annie Bett's whereabouts. For the remainder of the evening, Stefan alleges he remained in his car, weeping inconsolably, fears of inability to save Astrid overwhelming him.
Lastly, Sandy enlightens Tosh and Ruth, revealing that data extracted from the Jakobson vehicle has unveiled new leads in the intricate web of deceit and desperation.
The GPS records from that fateful night reveal a clear trajectory: Stefan embarked on a journey from his home to the laboratory and subsequently returned, never venturing anywhere close to the croft. Meanwhile, Ian Bett reached out to Ruth, and Billy imparted to Tosh that Stefan渴望与他的女儿对话。 On another note, Ian filled Ruth in on Euan Rossi's involvement. Ruth, eager to discuss Rossi, dialed Rob Harding (portrayed by Michael Higgs) but had to leave a message, requesting him to callback at his earliest convenience.
Sandy, sharing vital information with Tosh, mentioned that he had retrieved the admission logs for the day Anton accompanied Astrid to the hospital. Given that Annie was simultaneously in the Accident and Emergency department, the possibility arose that their paths had crossed there. Intriguingly, Sandy added that Annie had accompanied someone else.
Tosh paid a visit to Tara Kirk (Nalini Chetty), who disclosed that they suspected Anton and Annie's encounter took place within the walls of Lerwick Hospital. Tara inquired if Tosh had perused her medical records, to which Tosh responded she was solely focused on Annie. Tara revealed that she had been experiencing a miscarriage, a development unknown to Frank. After some hesitation, Tara acknowledged recalling both the girl and the boy. Although she didn't witness Annie conversing with him, she did remember Annie's parents waiting outside and Annie appearing somewhat perturbed.
Later, Donnie (Angus Miller) cross-examined Tosh about her conversation with Tara, leading to a heated exchange between them. Tosh insisted that they were strangers to these individuals, their lives shrouded in mystery.
Stefan was granted permission to converse with Astrid over the phone, during which Astrid confessed her exhaustion with the current situation. They pondered taking a break and attempting to rebuild their life as a family. Meanwhile, Rossi's phone buzzed with an incoming call. When Rob finally connected with Ruth, their conversation was brief but to the point. Rossi inquired about a drop-off location, oblivious to Rob's silent communication to Ruth about receiving the message pertaining to Rossi. As Rossi busy himself retrieving a firearm, Rob urgently informed Ruth of the necessity to apprehend Rossi, cautioning her about his perilous nature.
