Between their busy lives and their far-flung residences, the Mother-Daughter Book Club—four longtime college friends and their five daughters—more often discuss the books on their nightstands via 2 a.m. texts than in-person meetings. And maybe it’s just as well, after what happened at their last get-together …

So it’s an emotional reunion when they finally gather again, this time on the spectacular shores of Italy’s Lake Como. Sightseeing excursions, reminiscing fueled by “Como-politans,” and a hint of vacation romance all build toward the book club’s trademark “Night of Secrets.”

These friends, and sometimes rivals, are close readers of novels, memoirs, and of each other. But as the years and the distance cast shadows and doubt, confidences and sympathies turn into surprising revelations.