January 1975. Student nurse Heather Pearce dies during a training demonstration. Detective Chief Inspector Adam Dalgliesh is sent to investigate, accompanied by his partner DS Masterson. Pathologist Dr. Chopra confirms that Pearce was poisoned. Dalgliesh and Masterson take statements from the nurses, despite Matron’s attempts to intercede.

After Fallon’s death, Dalgliesh finds a library book in Fallon’s room and a letter in Pearce’s pigeonhole about a patient of Courtney-Briggs’ called Martin Dettinger, whose recent death on the hospital ward upset her. He later discovers rose spray, which Chopra confirms was used to poison Fallon. In the woods Dalgliesh is violently attacked.

March 1975. Dalgliesh is invited to Dorset by his old friend Father Michael, only to discover that he died a few days ago. Father Michael lived in a home for the disabled run by the enigmatic Wilfred, who has organised trips to Lourdes ever since he was miraculously cured there of a serious illness.

Wilfred announces that he will transfer the Grange to the Ridgewell Trust and hold a vote on whether he will carry on as spiritual adviser. Maggie threatens to down the ‘whole rotten place’. Despite Eric and Helen’s plot to usurp Wilfred, the majority of the Grange vote for Wilfred to stay, ensuring the Lourdes trips will continue.

May 1975. 8-year-old Darren and churchwarden Miss Wharton find two dead bodies in the vestry of St Matthew’s Church, Paddington, their throats slashed. One is Sir Paul Berowne, a baronet and recently-resigned Tory MP; the other a homeless man called Harry Mack. Dalgliesh is called in to investigate, accompanied by DS Masterson and his new DS Kate Miskin.

After the attack on Father Barnes while Halliwell was in custody, Dalgliesh brings Swayne and Lampart in for questioning. He discovers Lampart is having an affair with Lady Barbara, who reveals she is pregnant and thinks she will inherit everything. However, Lady Lavinia reveals that Sir Paul secretly changed his will at the last minute.

When a senior forensic biologist is found dead in his lab, Dalgliesh is called to East Anglia, where the murderer is lying in wait to strike again.

After another body is discovered, Dalgliesh and Miskin untangle a web of infidelities in this rural community, unearthing a killer with secrets to hide and tracks to cover.

Dalgliesh, Kate Miskin, and new D.S. Daniel Tarrant investigate the murder of an abrasive female defence barrister who successfully defended a shady young man on murder charges, only for him to begin dating her daughter.

As Dalgliesh's team sort out the complicated motives surrounding the victim's murder, they are running out of time to save her daughter from her dangerous fiancee.

Marcus and Caroline Dupayne struggle to convince their brother, Neville, to renew the lease on their family's museum. When Neville's car is torched on the museum grounds and he perishes inside, all who work there are suspects - including his siblings.

The grisly discovery in the trunk provides a new line of inquiry that leads to a hidden room, ties to intelligence agents, and a scandalous society at the heart of the museum. The team race to crack the case as the killer prepares to strike again.