When a mysterious killer bent on revenge begins targeting members of her family, Cissy Cahill must unravel a deadly mystery linked to her family's secret past before she becomes the next victim.

Thirteen-year-old Dan Cahill and his older sister, Amy, thought the search for the thirty-nine clues leading to the source of their family's power was over, but when Cahills are kidnapped by the Vespers, Amy and Dan find themselves with only a few days to fulfill a bizarre ransom request before their friends start dying.

Operation Trinity chronicles the first Vesper attack on Jan van Eyck's altarpiece at Ghent in the 1600s, then jumps to WW II and young Grace Cahill's desperate bid to save the masterwork from the Nazis.

Returned by a surprising twist to their first mission on U.S. soil since the beginning of the Clue hunt, Amy and Dan discover evidence of a mole in their organization who proves to be one of their closest confidantes and who reveals, even more disturbingly, the true agenda of the Vespers.

"San Diego private investigator Rick Cahill's past comes back to haunt him when he's at his most vulnerable. His wife, Leah, has fled with their daughter, Krista, to her parents' home in Santa Barbara. She fears Rick's violent outbursts brought on by his potentially fatal brain disorder, CTE-and she doesn't trust that he'll ever be able to tame his manic desire to bring his own brand of justice to an unjust world. Rick desperately wants to reunite...