Nearly twenty years after the events of Mortal Engines and Predator's Gold, Tom and Hester have finally settled down. The wild adventures of their past are now little more than stories to tell their daughter, Wren, who relishes their adventures just a little bit too much. Her foolhardiness gets her kidnapped—and worse, whisked right back into the very world her parents thought they'd left behind. To rescue her, Tom and Hester must jump headfirst back into danger. Their pursuit will reunite them with enemies they thought they'd left behind forever, will ask of them sacrifices that no parent can make, and will cost one of them everything that matters most.