The series revolves around five different characters from different parts of Britain: David Sowerbutts (played by Pemberton), a
serial killer obsessed man-child who still lives with his mother Maureen (Shearsmith); Mr. Jelly (Shearsmith), an embittered one-handed children's entertainer; Oscar Lomax (Pemberton), a blind millionare who collects
Beanies; Joy Aston (French), a
midwife who treats a practice doll as if it is her real child; and Robert Greenspan (Tompkins), a
telekinetic panto dwarf in love with his
Snow White. All five are connected by a mysterious
blackmailer who has sent them a letter each, all of which contains the same message: "I know what you did…"