Agatha Christie 
The Seven Dials Mystery [PDF ebook] 
Another Gripping Novel From the Queen of Crime

A healthy young man dies in his sleep, despite the ringing of eight separate alarm clocks… Gerry Wade had proved himself to be a champion sleeper; so the other house guests 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 had backfired with tragic consequences. For Jimmy Thesiger in particular, the words ‘Seven Dials’ were to take on a new and chilling significance…