A cryptanalyst takes on a worldwide conspiracy targeting women.
This isn’t the first time Salem Wiley has reluctantly fought the powerful group known as the Hermitage or the Order. In fact, she was raised by her family, especially her unloving mother—a leader in the Underground, an ancient group fighting for women's rights—to uncover secret, long-buried clues that could help the women’s cause. Despite her agoraphobia, Salem has now joined the FBI’s top-secret Black Chamber. Her first assignment takes her to England, where U.S. President Gina Hayes will attend a conference, and Ireland, where a woman has called in a tip that Hayes will be assassinated while in London. The Irishwoman reveals a replica of Stonehenge that’s perfect but for an extra stone with the word "mercy" carved on it. Astonished by the revelation that Stonehenge has something to do with feminism, Salem keeps it to herself while she ponders whether mercy is a plea or something to do with Mercy Mayfair, a child she met when she and her best friend, Bel, thwarted an earlier attempt to kill Hayes. Salem’s assigned to work with Charlie Thackeray, a member of British Intelligence, rather than Lucan Stone, the FBI agent she has a crush on, who turns out to be in London along with Salem's mother, Vida, and Mercy Mayfair. While Salem uses her experimental computer program to learn more about Stonehenge, world-class assassins hired by the Hermitage plot to kill the president and Salem once she solves the puzzles. They kidnap Mercy to force her compliance. Salem’s search takes her from Stonehenge to the Orkneys and back to Ireland in a desperate and dangerous search for clues. Never knowing who she can trust and nearly crippled by her fears, she soldiers on, refusing to abandon Mercy.
A complicated page-turner of a history-based thriller whose predecessor (Salem’s Cipher, 2016) is virtually a prerequisite to understanding the tangled relationships and fascinating backstory.