Time is splintering. Stuck in 1763, Peter Schock and Kate Dyer begin to realize that history has reached a tipping point. Gideon and Peter hunt their enemy, the Tar Man, through the dark streets of eighteenth-century London, but there is a greater threat. The antigravity machine is in the hands of Lord Luxon, who has set his eyes on the most valuable prize of all: America. As Lord Luxon changes the past for his own gain, time quakes begin to sweep through history. Kate Dyer, adrift in time, realizes the terrible truth: If Lord Luxon is not stopped, the time quakes will tear the universe apart.