A practical joke goes chillingly, murderously wrong in Queen of Mystery Agatha Christie's classic detective story, The Seven Dials Mystery.Gerry Wade had proved himself to be a champion sleeper, so the other houseguests decided to play a practical joke on him. Eight alarm clocks were set to go off, one after the other, starting at 6:30 a.m. But when morning arrived, one clock was missing and the prank then backfired, with tragic consequences.For Jimmy Thesiger in particular, the words "Seven Dials" were to take on a new and chilling significance. . . .