After murdering a woman, an unidentified man stalks Robin Ellacott, whom he sees as part of his plan to exact revenge against private investigator Cormoran Strike.

Strike has developed a relationship with radio presenter Elin but continues to harbour feelings for Robin, whose fiancé Matthew disapproves of the work she is doing.

One day, Robin receives a package containing a woman's severed leg and a message quoting the Blue Öyster Cult song "Mistress of the Salmon Salt (Quicklime Girl)".

He then approaches Detective Inspector Eric Wardle with four possible suspects, three of whom he knew from his time in the SIB: To Strike's annoyance, the police only focus their investigation on Malley because of his previous tactic of mailing body parts.

Strike and Robin decide to initiate a parallel investigation, which they begin by reviewing 'unusual correspondence' that had been sent to the office throughout the years, stored in what the pair light-heartedly call the 'nutters' drawer.

[2][3] Cormoran Strike – a veteran of the war in Afghanistan and an ex-SIB investigator who was honourably discharged from the military after losing half of his right leg in a bomb attack.

In The Guardian, reviewer Christobel Kent called the novel "daft but enjoyable", with a "narrative dizzying in its proliferation of character, location and detail, and tirelessly, relentlessly specific."

Rowling acted as executive producer of the series through her production company Brontë Film and Television, along with Neil Blair and Ruth Kenley-Letts.