Roy Barlow and Alex Blain, two Detective Inspectors from different ends of the country, have used unorthodox practices in the past to solve crimes. Attending a training course in the Midlands the pair meet. Someone out there knows them both and sets about on a murderous spree in London and Leeds to discredit them both. The signature of the killer is that he leaves a short diary on each body detailing how he stalked the victim. The two detectives resort to type and call in the people who helped them in the past. Little do they know that one of the Detective Inspectors becomes earmarked as the next victim. Will they realise in time? Will the killer nicknamed the Diary Man prevail?