[1] Amy and Dan Cahill, the protagonists of the series, try to follow a Lucian secret which was stolen by the Nazis during World War II.

But on the way to the Cairo International Airport, they are chased by Ian and Natalie Kabra, competitors in the race to find the 39 clues hidden around the world.

Amy and Dan hide in a coffin while he lures Irina and two Lucian agents out of the church in an attempt to help them escape.

They safely make it out of the Church on the Blood, and with Nellie on her way, Dan calls Hamilton and gives him the clue, 1 gram of melted amber.

The Horn Book Magazine said, "The series still pushes credulity past the tipping point, but these installments introduce new developments (heretofore cartoonish competitors reveal hints of humanity; the sibs' stalwart nanny becomes suspicious; clues to their parents' death surface) that rejuvenate the foundering plots.

"[2] Sarah Schowengerdt called the novel a "fast-paced volume" in the Cricket Media children's magazine Faces: People, Places, and Cultures, while The Darien Times said of the story, "Full of danger and intrigue—a great game of cat and mouse!