The creator of the Enzo Files and the haunting Lewis trilogy, Scottish-born novelist Peter May has also written and produced top-rated drama series for British television, and been awarded the CEZAM Prix Litteraire—the national literature award in his adopted home of France.

Having solved—and survived—his third investigation in Blacklight Blue, forensic expert Enzo Macleod encounters an irresistible puzzle on tiny Ile de Groix, off the coast of Brittany. The private study of Adam Killian has lain untouched since his murder some 20 years earlier, left in the care of his daughter-in-law Jane as a coded puzzle that only his son Peter could decipher; unfortunately, Peter himself was killed in a crash before he could return. Jane's last hope for resolving this double tragedy is Enzo, but the man acquitted for Adam's killing has gone into hiding—and the rocky island itself holds a surprising revelation for Enzo.