Episode 9 of Dept Q kicks off its gripping finale with an incriminating interview featuring Lyle Jennings. On camera, he lays bare the childhood trauma he and Harry endured, revealing their mother's brutal use of a hyperbaric chamber as a punishment tool. Ironically, this same chamber now holds captive Merritt, the latest victim in a chain of events. Lyle recounts how he was confined within its confines for prolonged periods, a harrowing experience that ultimately molded him into a sociopathic figure. He's haunted by the conviction that Harry's spirit lingers by his side, finding it perplexing to grasp that the shadow he constantly trails is Sam Haig, not his brother Harry.
Ten years prior, Lyle was liberated from the confines of Godhaven, yet his subsequent whereabouts, after being transferred to the Rampton EPD unit, remain shrouded in mystery—a psychiatric hospital that eventually saw him return to Mhor, intertwining all facets of his life.
Meanwhile, Cunningham uncovers vital clues. Logan makes an appearance to confront Moira, probing into the Leith Park incident. He drops a bombshell, disclosing his discovery of Anderson's involvement, which unlocks a new avenue of investigation. Inadvertently, he reveals that Carl has unearthed this pivotal information, prompting Moira's concern over her own stagnant progress on the case.
Cunningham, though not devoid of competence, arrives at the Jennings' abode to deliver Ailsa her mail and inquiries about a mysterious 999 call traced to her mobile phone. This call coincides with Merritt's frantic plea outside the hyperbaric chamber, heard in the cliffhanger of the previous episode.
Ailsa dismisses it as a mere oversight, but Cunningham shifts his focus to Lyle, his suspicions heightened for her safety. His detective work pays off as he deciphers that the 999 recording captures Merritt's desperate screams, echoed through the confined space, hinting at her proximity.
The urgency escalates as Lyle and Ailsa literally turn up the heat, the temperature inside the chamber spiraling out of control. Merritt, glancing outside, catches a glimpse of Cunningham. Amidst his heated confrontation with Lyle, filled with accusations and rage, Cunningham resorts to drastic measures, pounding Lyle into submission with a hammer, the intensity of the moment palpable.
What unique contributions does William bring to the team? In Carl's efforts to mobilize the group (comprising William and Claire), they delve into the intricacies of this case, rooted deeply in their shared history with Harry Jennings and the violent altercation that once befell William. Flashbacks unravel the sequence of events, revealing that following a robbery, William, in a moment of desperation, struck Harry in the head with a stick. However, it wasn't Harry who meted out the savage beating to William that fateful night; it was Lyle, relentless in his assault until Harry intervened, delivering a powerful kick to Lyle's face that not only disfigured him but also spared William's life, albeit leaving him physically impaired from the ordeal.
Haunted by these memories, William's current behavior is a storm of lashing out, yet Claire understands this as a mask for his underlying fear. Furthermore, it transpires that Lyle's presence aboard the boat triggered William's terror, leading him to strike Merritt out of recognition and subsequent panic.
What became of the genuine Sam Haig? The authentic Sam Haig sought reconciliation with Lyle, hoping to mend fences from their troubled past. Unbeknownst to Sam, Lyle harbored darker intentions, using the pretense of reconciliation to plan his next move. After noting Sam's license plate, Lyle boarded the ferry disguised as a worker and, with the aid of his mother, abducted Merritt.
On the day Sam met his untimely end, he spotted Lyle heading towards a cliff and decided to discreetly trail him. Sensing he was being followed, Lyle turned the tables, brutalizing Sam until he was barely recognizable. With Sam's keys and gear in hand, Lyle dragged him to the cliff's edge and shoved him off, staging the scene to look like a climbing accident by smearing clay on his hands. He then planted Sam's belongings in the backseat, eliminated fingerprints from the car, and fled with the keys, tying up all loose ends with cold precision.
Unveiling the Jennings family's checkered past, the saga entangling Merritt reaches a boiling point. With the impending revelation, Lyle and Ailsa devise a stealthy exit strategy, meticulously erasing all traces of their presence, save for the oppressive pressure contained within the hyperbaric chamber. Lyle painstakingly scrubs away fingerprints, ensuring no evidence remains, before departing with Ailsa.
Meanwhile, Akram and Carl venture once more to Mhor, their journey culminating at the Jennings' secluded compound. Through their relentless pursuit, they uncover Merritt's whereabouts. Simultaneously, Rose delves into the depths of the family's secrets, her findings painting a grim picture that is far from uplifting.
Following Clive Jennings' untimely demise—a grim act orchestrated by Lyle, whose own past is marred by violence and turmoil—Ailsa found herself confined to involuntary psychiatric care for a harrowing 19 months. During this prolonged absence, Lyle and Harry were left unsupervised, a period that saw the fateful involvement with the hyperbaric chamber.
At the tender age of 15, Lyle's macabre curiosity led him to force another youthful victim into the decompression chamber. He systematically escalated the pressure, eager to observe the point of consciousness loss, an experience that planted the seed for his future plans to harm Merritt.
The enigmatic bird sigil, a recurring motif, is intertwined with Shorebird Ocean Systems, a company that Hardy meticulously scrutinizes online, diving deep into the world of hyperbaric chambers.
Within the confines of a dimly lit warehouse, Carl and Akram uncover a grim discovery: Cunningham, lifelessly slumped in the trunk of his police cruiser. Their investigation propels them towards a hyperbaric chamber, where Merritt is perilously confined. With urgency, they race to halt the escalating air pressure, ultimately stabilizing it through Hardy's intervention—but not before Lyle interrupts, firing a shot that strikes Carl. Akram shields him, providentially sparing both from mortal harm. United in adversity, they overcome Lyle, securing Merritt's rescue in the fray.
As Merritt lies on a hyperbaric stretcher, en route to safety with meticulously regulated pressure, William arrives on the scene, thanks to Moira and her helicopter, reuniting with his sister. Meanwhile, Ailsa attempts a sneaky exit but is promptly apprehended by the police. Rather than confront incarceration, she takes her own life with a harrowing self-inflicted gunshot.
The resolution of the case brings Carl back to his familiar surroundings, where Rachel, Jasper, and Martin await, astonished yet again to witness his wounded form. Carl bears his wound with pride, knowing he acted selflessly to safeguard Akram and the day.
Months later, a recovering Merritt returns to the station, offering heartfelt gratitude to everyone except Carl, who has stepped away for a well-deserved break. Merritt too prepares for departure, escorting William back to Mhor to reconcile with her father. With a newfound clarity, she intends to mend her relationship with Jamie for good.
How does the inaugural season of Dept. Q conclude? In Stephen Burns' office, he discovers Carl awaiting him, poised to discuss the Kirsty Atkins ordeal. Burns has reached a decision: he will refrain from denouncing Carl for his collaboration with Finch, a choice rooted in his own fatherly empathy—yet, this leniency carries conditions.
Carl, unyielding, insists on a fair budget allocation for his department from the Lord Advocate and urges the swift promotion of Akram to Detective Inspector. Despite being a political asylum seeker, Akram's prowess and loyalty are beyond reproach; his bravery, even extending to taking a bullet for Carl, speaks volumes.
Carl, accompanied by Rose and Akram, retreats to their basement office, ready to delve into more enigmatic cold cases. However, their workspace is not devoid of intruders. Hardy makes his return, storming into the police station on crutches, a figure of undeniable presence. Moira has a case in mind for him, albeit not directly tied to Carl. The implication hovers in the air: Hardy might be tasked with overseeing the Leith Park mystery.
