The fourth episode of Shetland's ninth season delves deeper into the intricate web of secrets and lies that have enveloped the island community. As DI Ruth Calder and her colleague Tosh navigate through the aftermath of Annie Bett's murder, they find themselves entangled in a case that strikes close to home for Tosh, revealing hidden layers of deception and a race against time to uncover the truth.
The episode begins with a poignant flashback, depicting a young Fergus Harris learning the ropes of mussel fishing from his father, John. The scene is a stark contrast to the present day, where tragedy strikes the Harris family. John, in a moment of anger and confusion, accidentally kills Fergus with a metal claw from their mussel fishing boat. The shock and grief are palpable as Patrick, Fergus's brother, calls for help while John performs CPR in vain.
Calder and Tosh arrive at the Harris house to find John refusing to let go of Fergus's body. Patrick, in a state of shock, recounts the argument that led to the accident and admits to breaking into the Bett house to steal money to pay off a debt. He vehemently denies killing Annie and Bergen, casting doubt on the initial suspect, Euan Rossi. At the police station, John is devastated, and Tosh's empathy for him is evident. Meanwhile, Billy provides Tosh with flight details that Annie had been investigating before her death, adding another layer to the mystery.
The tension escalates at the Jakobson house as Karin and Stefan's relationship remains strained. Stefan discovers Astrid missing and insists on finding her without involving the police. Astrid is later seen wandering along a remote road, hiding from a passing car, indicating that she is on the run.
Calder's pursuit of a search warrant for the marine research facility is initially met with resistance from her boss, Harry. However, a connection is made when Sandy reveals that the facility is funded by the same company chartering flights Annie was investigating. This revelation leads to the discovery of a secret lab within the facility, where Doctor Mohan has been conducting unlicensed stem cell treatments for Astrid Jakobson.
As Calder and Tosh question Doctor Mohan, they learn that Bergen had tried to stop the medical trial, leading to a confrontation with Stefan. Astrid, still missing, is found by Nathan, who agrees to help her escape the island. Meanwhile, Tosh and Calder head to the Jakobson house, only to find Astrid missing and her passport gone, suggesting she might be trying to reach her birth mother in Tallinn.
The episode takes a dramatic turn when Stefan is arrested for Bergen and Annie's murder, based on Karin's tip-off. However, his alibi checks out, leaving the investigation at a standstill. Meanwhile, Astrid's condition worsens as she hides in a truck, leading to a frantic race to find her before it's too late.
The episode concludes with a chilling development as Euan Rossi, who has been watching Ian and Noah, confronts Ian, claiming to have known Annie longer than Ian did. Rossi's true intentions remain unclear, but his possession of a gun similar to the murder weapon raises the stakes significantly.
In this episode, the lines between friend and foe blur, and the race to uncover the truth behind Annie's murder becomes a dangerous game where no one is above suspicion. As the secrets of Shetland's residents are laid bare, the investigation takes a toll on the personal lives of those involved, culminating in a gripping and emotional journey that keeps viewers on the edge of their seats.