“When Stars Grow Dark” is the seventh outing for Detective Chief Inspector Brendan Moran, an authoritative homicide investigator with an eclectic Thames Valley team. This time a car crash reveals an aged man clearly dead before the accident, which soon segues into a baffling serial killer mystery. At the same time, an ongoing spy-linked thread, tying Moran back to his Garda days in Ireland spirals out of control and drags him to Rotterdam. A sparkling series this is indeed, and I judge this book to be the highlight. Cunningly plotted, superbly paced, imbued with locales bucolic and otherwise, When Stars Grow Dark is notably graced with an involving ensemble of police characters that, for me at least, evoked the mastery of Garry Disher with his brilliant Peninsula Crimes series. I can feel certain this sparkling mystery will rank among my crime fiction exemplars of 2021.