The Danish crime series DNA has returned to UK screens with a second season featuring the troubled detective Rolf Larsen, played by Anders W Berthelsen. What it has to offer is a storyline that’s as intriguing as it is harrowing. While DNA is often used to identify perpetrators in real life and in crime shows, the programme looks at some of the other ways it’s relevant in modern policing, and the human side of the cases involved.

Convinced his baby daughter was trafficked to France as seen in the first season, Larsen has been spending time there with a young mother and a child he believes is his baby. Explaining his theory to her is… awkward… and soon she loses patience with him. Meanwhile, in Denmark Larsen’s ex-wife has remarried and has given birth to a baby girl. However, there are complications and the child may need a new liver so the father, Thorstein, considers entering the black market for an organ.

With what he’s been through, Larsen is loath to allow the baby to die, so agrees to help Thorstein. However, the organ supplier turns out to be a very crude gang and soon Larsen and his colleague Neel (Olivia Joof Lewerissa, pictured with Berthelsen above) are led to a devastating scene, with mutilated bodies and multiple fatalities.

Across the continent, in Romania, Mario Montescu (Mario Zaharia) decides to follow his sister and her boyfriend to Western Europe. He believes something has happened to his sister and allows himself to be trafficked in the hopes of finding her supposed new employers and reasoning with them. However, he finds himself sold to a construction boss. Without papers he is held captive, with his boss claiming he’ll be paid after room, board and his debt are deducted.

There’s an eerie sense that whatever happened to the people Larsen discovered might happen to Mario, his sister, her boyfriend and/or the other young people trafficked.

While you’ll question Larsen’s decision-making, as the episodes unfold you’ll start to understand his perspective and his emotional state. Not only has he worked cases involving trafficking, he believes his own family has been a victim of it. A strait-laced cop just wouldn’t feel realistic given what’s happening. DNA is a show that hits hard from the very first episode, with varying levels of peril across storylines in locations including Copenhagen, Paris, Romania and wherever the trapped young people are being held.

As the series progresses, Larsen will work with Claire Bobin (Charlotte Rampling) of the French police once again, who comes to Copenhagen to share her expertise in dealing with organ trafficking. A conspiracy unfolds that could go all the way to the top.

If you enjoyed The Missing with James Nesbitt, and its spinoff Baptiste starring Tchéky Karyo, then DNA will be right up your street. Obsession, desperation, anger, resentment – they all build in the characters, clouding judgement and creating a constant conflict between rational investigation and an irrational need to act.

DNA was written by Torleif Hoppe and directed by Hans Fabian Wullenweber. Season two consists of six 45-minute episodes, airing in pairs on BBC Four from Saturday 26 August, and available here on iPlayer.