Instalment eighteen of an illustrious police procedural series, starring Chief Inspector Armand Gamache, Chief Inspector of the Sûreté du Québec, “A World of Curiosities” showcases the nimble storytelling gymnastics of Louise Penny in the service of a twisty, dark plot. Into Gamache’s bucolic home village of Three Pines come two young adults whom he rescued, years ago, from their mother’s murder. Are they healed or warped, Gamache ponders, as an inexplicable mystery, a painting of the “world of curiosities” of the title, is discovered, unfolding an escalating series of portentous messages. Penny is an adept stylist, taking the reader between the points of view of Gamache, his police offsider, and various other characters, and the first half of the book mightily impressed me. But then the burden of seventeen earlier unread mysteries began to weigh down on the plot, the inevitable freight of an ever-expanding cast of characters clogging the tale, until an evil echo from a prior book suddenly popped up unbidden. The final third of the novel became increasingly baroque and over-dramatised, and, not for the first time, I finished A World of Curiosities reflecting that mystery writers with long series eventually lose themselves in relationship tapestries that sap all tension.