The body doesn’t lie, even when the mouth does. For psychologists, body language can say much more about a situation than words ever can. Even the most hardened liar finds it hard to control the often minuscule signals the body shows that undermine what they are saying.

In Johana Gustawsson and Thomas Enger’s first writing collaboration, Son, those silent signals become almost deafening. Psychologist and police consultant Kari Voss is nicknamed The Human Lie Detector – with good reason. Every conversation with Voss can be read on two levels, the spoken and those unwittingly revealing signals that belie the innermost thoughts.

Finding herself drawn into the investigation of the brutal murder of two teenage girls in a summer house just outside Oslo, Voss finds a web of lies that reaches back into her own tragic past.

It’s not just verbal and non-verbal communication that can be read on two levels here, even the title Son is a double-edged sword. On one level it refers to the small town where the teenage girls’ bodies are discovered. An affluent fjord-side town, Son is an idyllic refuge just 40 minutes from Oslo. For Voss though, it is her own son, Vetle, who is always present in her mind. Seven years ago, the young boy vanished on his way home from his friend Jesper’s house on his ninth birthday, an event that still haunts her.

That personal link hits harder when the police arrest Jesper as chief, and only suspect, for the girls’ murder. Despite having worked with the police for decades as a consultant, and the daughter of the former chief of Oslo police, Voss thinks they’ve rushed to frame an innocent boy.

Gustawsson and Enger’s creation of Voss is perfectly pitched. There’s a lot of science and psychology at play behind her that could easily turn into an academic thesis, but the writing duo make Voss utterly compelling. A woman attuned to every gesture, the sheer wave of unfiltered human emotion is vividly painted and at times threatens to overwhelm the consultant, but for the reader, it provides a real depth of detail that convinces and keeps readers hooked.

There’s more to Son though than just Voss, and every character here is fully fleshed out to bring this story to life. There’s two families coming to terms with unbearable loss, each family with their secrets and dramas overlapping with the investigation, and Chief Inspector Ramona Norum, a long-time collaborator and admirer of Voss who finds herself having to question her own police instincts. Together it all creates a fully formed world that gives a solid background for a thrilling plot resplendent with plenty of twists and turns to make this a compelling page-turner.

There’s often a feel in the first instalment of any new series that plot is somewhat sacrificed on the altar of character introduction and exposition setting up future instalments. There’s nothing further from the truth here as the plot hits the ground running and doesn’t release its grip on the reader until the last unexpected final line.

There may be two hands at play here writing Son but it’s a seamless merging of voices, with a combined narrative so strong that it’s impossible to tell which writer crafted which line. That blending is even more impressive when you realise the two writers speak two different languages (French and Norwegian), are based in two different countries and came together to write the book in a third, mutual, language – English.

With a cliffhanger on the final line, there’s already eager anticipation for the next instalment of what, if this debut offering is anything to judge by, is set to become a must-read Nordic Noir series.

Son by Johana Gustawsson and Thomas Enger is published by Orenda Books on 27 March 2025.