Morse's friend Beryl Newsome is stabbed at a rehearsal for an amateur production of The Magic Flute. Then Lewis starts uncovering incriminating evidence,
including the transfer by the murder victim of ·99,000 into Morse's bank account. With his rival Bottomley pursuing him, Morse finds himself at the top of the suspect list and is eventually arrested for the murder he is investigating. After his arrest, Morse's house is searched, and a clergyman's body is found in a cupboard. With Morse seeing a Masonic conspiracy, Lewis suspects that someone with a grudge is out to frame Morse, partly by hacking into computer systems.
After his release, Morse becomes the target of a direct attack, when his house catches fire, with him in it. Who wants to get at Morse so badly? Can it really be an old enemy who is dead?