Alex Packard is a senior London police officer who is also is a minor recreational drug user. He is estranged from his family because of this and his wife's philandering. Nevertheless, it is while he is recuperating from a gunshot wound, received while attempting to arrest an IRA bomber - who escapes - he is offered the chance to go to Perth in Australia and investigate a skeleton thought to belong to Jack the Ripper. But first, Alex goes to Broadmoor Psychiatric Hospital to speak to Carol, who the British Home Office have revealed to be Jack the Ripper's great-granddaughter.
Alex and a colleague take with them to Australia never before released DNA taken from the hand of Jack the Ripper's second victim and they are able to prove the bones belong to Jack the Ripper; a former 19th Century policeman named as Jack Blade. Blade had been apprehended in 1888 but escaped the justice system with considerable help from influential people and is sent to Australia where, eventually, he continued to murder.
When Blade's sons finally get their father locked up in a local psychiatric hospital they build a chamber under their house to contain their mad father when he's released. This where he stays until he dies in 1943 and it is where he's discovered seventy years later.
Michael Coglin, the IRA gunman is found and shot dead by Perth police at a casino but not before Coglin shoots a local police officer.
Ben Blade, Jack's grandson is interviewed in hospital and fills in many useful details but he dies shortly afterwards. Alex is upset by Ben's death and mystified when Jack Blade's house mysteriously burns to the ground and believes it was arson. But now Alex's mental state is being questioned after he claims he actually spoke to Jack the Ripper in their hotel.
Back in London, and still in a lot of pain from the wound to his leg, he is confronted by Jack the Ripper's ghost again who takes Alex, in his pyjamas, on a tour of 19th Century London to meet the Police Commissioner, Sir Charles Warren and other 19th century notables involved in the case - including the murder victims.
Right from the start, Alex,has been harrassed by Jack the Ripper's ghost with visual and auditory hallucinations. Alex stops work and retrats to his basement flat where he begins his final slide into madness - caused by drugs and Jack the Ripper's continual interference in his thought processes. Finally he receives auditory command hallucinations that tell him to murder his wife when she turns up to enquire why he hasn't bothered to attend his son's birthday party. Alex stabs her to death while Jack the Ripper watches on.
For Alex his trial is a mixture of visual hallucinations and conversations with Jack the Ripper's victims. Once convicted, Alex is sent to Broadmoor, where he continues to talk to the ghosts of all the people involved in his destruction for the next 50 years. Alex is actually looking forward to joining Jack the Ripper's ghost in the after-life to begin his work as a malelovant ghost.