Masterpiece Mystery "No platform for racists!" shouts a crowd of protestors, interrupting the controversial lecture of American academic Paul Yelland, a guest of Oxford's Department of Criminology. An anti-racist extremist hurls a threat at the prof... (more)essor, and later that night, Yelland is discovered strangled to death with a noose made from his own tie. The investigation draws Inspector Lewis and Hathaway into a criminology department rife with murder suspects, many of them already guilty of lesser crimes. Star student Nina Clement is having an affair with the husband of the coldly ambitious department head Anne Rand, who brought Yelland to Oxford solely to generate attention for her department. Now, with the papers headlined "Lynched," she relishes the publicity. But in an atmosphere of racial tension made worse by Yelland's "theory of dangerousness," which asserts that evil can be located in genetics, Lewis and Hathaway must move quickly to find the killer. Genetics have no place in their investigation; it's motive — whether politics, ambition, or vengeance — that will reveal the indelible stain of murder.