When a newly-appointed Catholic bishop disappears shortly after receiving a macabre gift in the post – a severed human tongue – the Vatican calls in Peter Ash of the European Crime Division to help. Enclosed with the package was a bizarre note: Memini Bonn. I remember Bonn. At the same time, Ash’s Swedish counterpart Frankie Varg is investigating the murder of a prominent politician. When it transpires that the two cases are linked, the pair team up to become enmeshed in a baffling investigation where nothing is as it first appears. What exactly is the significance of Bonn? And who is so determined to unleash those carefully buried memories…?