Morse investigates the murder of Trevor Radford, managing director of the family-owned Radford's Brewery, who was attacked and killed while working late. Morse becomes immersed in the implications of a hostile take-over bid by another company. Then Helen Radford goes to the brewery to look for her missing husband Stephen and finds him also murdered.

The apparently motiveless murder of two young women points to a psychotic killer. Morse's speculations on what they might have in common leads him to a local garage owner, Jeremy Boynton, who knew them both, and who arouses his suspicions and dislike. Convinced that Boynton holds the key to the crime, Morse begins to hound him, despite having no firm evidence. Morse is also faced with the possible oss of his beloved red Mk II Jaguar.

Morse finds himself at the top of the suspect list when his lady friend, Beryl Newsome, is stabbed at a dress rehearsal for the local amateur dramatic society's production of The Magic Flute. Then Lewis starts uncovering more incriminating evidence, and Morse becomes the target of direct attacks. Who is it that wants to get at Morse so badly?