Claire Montrose, the Portland (Ore.) gal with a fondness for vanity license plates and a penchant for trouble, finds plenty of both in this fourth solidly entertaining mystery from Henry (Heart-Shaped Box, etc.). Claire's accidental discovery of an unusual diamond ring embedded in an old stone wall has a startling effect on her housemate, Charlotte ""Charlie"" Heidenbruch, an octogenarian concentration camp survivor. Charlie recognizes the ring as one that belonged to a beautiful young women she knew more than 50 years ago. The woman's tragic and inexplicable suicide still haunts the group of friends that dispersed after her death. As Claire and Charlie try to find the ring's rightful owner and learn how it came to be buried in the wall, the surviving members of the old group begin to reconnect with deadly results. Cozy trappings, from Claire's ditzy mother's antics to developing romantic relationships, effectively contrast with chilling glimpses of Charlie's concentration camp days and interludes of seemingly unrelated modern-day hate-crimes in Portland. A vivid cast of elderly characters, including Frank, whose newfound popularity can be traced to his ability to drive at night, and Nova, who continues to live as recklessly as ever, will especially please senior fans.