There are some individuals in this universe who follow fear and trouble. They are drawn to it like a magnet, ending up time and time again in places rife with threats and danger, full of enemies at work or monsters at large. They arrive in the nick of time, when all seems darkest.
Then there are others, in this wide, nigh-infinite universe, who seem to follow sorrow. They are drawn to heartbreak and defeat. They lurk in the shadows of the darkest of days and the worst of nights. They arrive, and bring the darkness with them. So hungry are they for sadness that they are called the Ravens of Despair.
This supplement for Doctor Who: Adventures in Time and Space includes full rules and background for the deadly Ravens of Despair, as well as loads of plot hooks and story ideas for pitting your own time travellers against their machinations.