Des tells the story of the arrest and trial of serial killer of one of the uk s most notorious criminals, dennis nilsen. The drama is told through the prism of three different men nilsen himself, detective chief inspector peter jay, and biographer brian masters.the dramatic series explores the personal and professional consequences of coming into contact with a man like nilsen who murdered several boys and young men in his flat from 1978 to 1983 and went undetected until police were called following reports of human fragments of flesh and bone clogging the drains.