Bailey, Thornton and Cryer were eighties entrepreneurs, until it was found that they had stolen millions of pounds from their investors.

All three are serving sentences in the same prison where Cryer is found dead in his cell. It looks like a heart attack, but the pathologist's report quickly points to murder.

Morse and Lewis go behind bars to investigate, but find they have to tread carefully with the prison governor, Mrs. Stephens, who is concerned about the reputation of her institution.