Two men have been found beaten to death in a Newcastle park. One is a mild-mannered librarian, the other a member of a gang of armed robbers from the 1970s. It's no mystery who killed them. But Walter Oyston - ex-boxer turned violent wino - is also dead, his heart having given out before his liver.

Is it a simple case of mistaken identity? Or have the ghosts of Newcastle's criminal underworld returned to seek vengeance on one of their own?

Following hot on the heels of their last investigation comes another baffling case for DCI Theo Voss and his team from the Bug House.