Seventeen-year-old Clocker Saira Elian is back on the run and being hunted by Mongers. The Descendants of War are amassing power in the 21st century, bent on controlling all the Immortal Descendants. Their attempt to kidnap Saira, a rare Descendant of Time and Nature, reveals just how brazen they've become. Archer, the vampire who has loved Saira for over a century, is willing to risk everything to protect her. When a horrific vision reveals Ringo, thief and loyal companion from 1888, being tortured at the hands of the bloodthirsty Bishop Wilder in a Renaissance prison, Saira and Archer realize there has been a ripple in the river of Time, and they must travel to 1554 to find its source and save their friend. Their rescue mission lures them to the Tower of London, site of the most notorious executions in history, where they encounter the mysterious Lady Elizabeth, who is confronting a terrible fate of her own. The time traveler, the vampire, and the thief will need all of their skills and ingenuity as they race against time to steal a document that could change the course of history and put the Immortal Descendants at the mercy of the Mongers. Can they stop a madman bent on collecting the blood of history's most powerful Seer before the executioner's ax falls?