John Rebus finds himself incarcerated for the murder of Cafferty. While awaiting his appeal, he learns of a murder in his cell block, a sort off locked-room mystery that ignites his detective instincts. Rebus must navigate the treacherous world of prison life, where alliances are fragile and danger lurks around every corner.  As always Rankin provides a multilayered whodunnit with a good number of breadcrumbs.