The 2025 TV series Dept. Q begins with Detective Chief Inspector Carl Morck returning to work after a traumatic shooting incident that left his partner paralyzed and another policeman dead. Carl is burdened by guilt and is assigned to lead a newly formed cold case unit, Department Q, which operates out of a semi-derelict basement office. This department is largely a PR stunt to improve the police force's public image, but Carl reluctantly begins to engage with the work.

The first major case assigned to Dept. Q is the disappearance of Merritt Lingard, a prominent civil servant who vanished four years earlier and was presumed dead. The team includes Carl, the logical and calm Akram Salim, and the ambitious Rose. Akram selects Merritt’s case as their initial investigation.

The narrative unfolds in parallel between the detectives’ investigation and Merritt’s own harrowing experience. Merritt is revealed to be alive but trapped in a pressurized chamber where she has been tortured for the past four years. The show alternates scenes between Dept. Q detectives piecing together clues from the outside and Merritt trying to understand who kidnapped her and why from inside her captivity.

Early scenes show Carl struggling with his personal demons and guilt, which affects his interactions with colleagues and his approach to the case. He suffers a panic attack after being forced to deliver a public statement about the Merritt Lingard case. Meanwhile, Akram presents the case to their superior, Moira, and they begin interviewing people connected to Merritt, including Fergus Dunbar, the detective who originally handled the disappearance, and Claire, who explains Merritt’s brother William’s disability and insists Merritt would never have abandoned him.

Carl also deals with personal challenges, such as discovering his son Jasper is skipping school and making an awkward advance toward Rachel during a therapy session. The investigation leads Carl and Akram to visit William’s care facility, but the director refuses them access. Carl confides in his friend James and is approached by Lord Advocate Stephen Burns, Merritt’s former supervisor, adding political pressure to the case.

As the investigation progresses, Merritt’s situation inside the chamber becomes more desperate. She learns the chamber’s airlock is broken while being delivered a meal, which adds urgency to her attempts to escape or signal for help. Flashbacks reveal Merritt’s clandestine meetings with Sam, who claims to be investigating corruption within the Crown Office. Merritt and Sam develop a personal relationship, complicating the mystery surrounding her disappearance.

The series builds tension by showing Merritt’s psychological and physical endurance in captivity alongside Dept. Q’s dogged pursuit of the truth. Carl’s team gradually uncovers layers of corruption and interference, including from high-ranking officials like Lord Advocate Burns, which had obstructed the original investigation.

The final episodes reveal the resolution of Merritt’s captivity and the outcome of the investigation. Merritt survives her ordeal, and Dept. Q’s efforts lead to exposing the perpetrators behind her kidnapping and the corruption involved. Carl, despite his initial bitterness and guilt, finds a renewed sense of purpose through solving the case and forming a team that challenges the system.

Throughout the series, Carl Morck lives, though he remains emotionally scarred but gradually healing. Merritt Lingard also survives, and the cold case unit Dept. Q establishes itself as a force to reckon with in solving difficult cases.

This detailed scene-by-scene narrative covers the main events visible to the viewer, including Carl’s return to work, the investigation into Merritt’s disappearance, Merritt’s captivity, the political and personal obstacles faced by the detectives, and the eventual resolution of the case.

The shooting that left DCI Morck badly wounded, paralyzed his partner Hardy, and killed another officer remains unsolved during the series. Morck suspects it was an inside job linked to DC Anderson, who had ties to a local crime boss and had suspiciously called in a fake wellness check before the shooting, but the assailants are not definitively identified in the 2025 series.

Merritt Lingard, a former controversial prosecutor believed to have drowned four years prior, is the central cold case that Morck and his team investigate. Akram Salim suggests looking into Lingard's disappearance, which becomes the main focus of Department Q's efforts, leading to breakthroughs that energize the team.

Carl Morck and Akram Salim develop a strong partnership marked by complementary skills and personalities. Akram, a Syrian former policeman, insinuates himself into Morck's basement office and becomes his de facto partner. Their dynamic evolves like a classic buddy cop relationship, providing both plot advancement and moments of humor.

Rose Dickson is a young constable who joins Morck and Akram in Department Q. She contributes to the investigation of cold cases, including the Lingard disappearance, and is part of the team chemistry that balances the group and helps advance the plot.

Morck's trauma from the shooting, which left him wounded and his partner paralyzed, causes him guilt and isolation. He is regarded as arrogant and antisocial by colleagues and is required to attend therapy sessions. This personal struggle influences his difficult relationships at work and his initial exile to the basement office, shaping his character's vulnerability and determination in solving cold cases.

The 2025 TV series Dept. Q is not family friendly and is officially rated for adults (TV-MA in the U.S., 15+ or 16+ in many other countries). It contains severe violence and gore, including direct scenes of people being shot and bleeding, and a dead man with a knife in his head shown multiple times, which can be very distressing. The show also features extensive strong profanity, with frequent use of words like "fuck," "shit," and occasional harsher terms, mostly from the main character.

Other potentially upsetting content includes moderate frightening and intense scenes, such as a man threatening a teenager with sexual violence. Alcohol use is present but mild and not a major focus.

In summary, the main potentially objectionable or upsetting aspects for children or sensitive viewers are:

• Graphic and repeated violent scenes involving shootings and death
• Frequent and strong profanity throughout the series
• Intense and threatening situations, including implied sexual violence
• Some alcohol use

Because of these elements, Dept. Q is suitable only for mature audiences, generally 16 or 18 and older depending on local ratings.