John Rebus spent his life as a detective putting Edinburgh's deadliest criminals behind bars. Now, he's joined them ... As new allies emerge and old enemies circle - and the days and nights bleed into each other - even the legendary detective struggles to keep his head. That is, until a murder at midnight in a locked cell presents a new mystery. They say old habits die hard... However, this is a case where the prisoners and the guards are all suspects, and everyone has something to hide.
With no badge, no authority and no safety net, Rebus walks a tightrope - with his life on the line. But how do you find a killer in a place full of them ?