The Dark Reckoning. The Cold War Legacy Series

A good deed turns into a search for a missing woman. When Isana Thomas finds a smartphone among the cherry trees, her life is put in jeopardy. Isana discovers the phone belongs to Lillian Hillam, whose son, Cyrus "Cy" Hillam, works at The Heritage Museum with Isana. But Lillian is missing, and someone doesn't want the pair to find her. Cy can't believe his mother would disappear without telling him, not after his father's suicide when he was a child.
Then kidnappers claiming to have Lillian contact him, asking to exchange her life for a list of names. Cy and Isana must delve deep into his parents' past to find the list and save his mother's life. But someone doesn't want them to succeed and will do anything to stop their search. Will Cy and Isana uncover the truth about the list before their lives are snuffed out?