San Francisco private detective Sharon McCone is asked to look into the case of Camilla and Jay Givens. It seems Camilla has been frightened by odd occurrences, the latest being a satanic ritual and baby sacrifice on an abandoned building site. Sharon wonders if Camilla needs a psychiatrist more than a detective but becomes concerned when she realizes that Camilla is frightened of her husband.
Meanwhile Sharon's husband Hy Ripinsky, head of an international security firm, is negotiating with the kidnappers of Van Hoffman, a muckety-muck who works for a government think tank. The kidnappers threaten to extract state secrets from Hoffman unless they're paid $45,000 - which happens to be the exact amount the Hoffmans have in their savings account.
When Sharon goes to investigate the 'satanic building site' she learns that her case seems to be connected to Hy's. It turns out that Jay Givens and Van Hoffman both belong to "The Night Searchers", a group of people that go on evening scavenger hunts. On these hunts they follow cryptic clues hidden all over the city to find a (supposedly) valuable prize.
When Hy has to leave the country Sharon is recruited to help with the Hoffman situation. She learns that Hoffman is an arrogant guy who's disliked by his family and about to lose his job. Simultaneously, Sharon's investigation of the Givens case reveals that Camilla may not be nuts after all.
Sharon recruits her nephew Mick to help her infiltrate the Night Searchers, a group that seems to contain a lot of weirdos and misfits. Some of Sharon's other relatives and the usual members of her detective agency also help with the investigation. In addition, Sharon is assisted by people in Hy's firm and - when she has to hide - makes use of one of Hy's safe houses. Unfortunately this is a defunct roach-infested motel with no electricity or water. Sharon perseveres and eventually uncovers information that helps resolve both the Givens and Hoffman situations, a resolution that some readers may see coming in advance.
Part of the pleasure of this series is visiting with the familiar characters, many of whom are on hand in this book. In the current story, some changes have occurred in the lives of Sharon and Hy; they've moved into a lovely new home after Sharon's old house was burned to the ground and are considering merging their agencies. The couple also promise each other an exotic vacation when they complete their current cases - something they both need.
I think this is an okay mystery that most fans of the series will enjoy.