With humans threatened by otherworldly creatures, orphans Emily and William Snow, and their friends-the pickpocket Spring-Heeled Jack and the wisecracking Corrigan-find themselves two hundred years in the past, trapped in the London of 1666. Desperately in need of help, they go in search of Sir Christopher Wren, who was head of the Invisible Order, an organization dedicated to fighting this threat. But Wren's never even heard of the Order and has no interest in their story.

Stranded, the four cannot agree on their next step. But they'll have to decide quickly, because their enemies are on the move and the Fire King is ready to attack and burn London to the ground.

Set against the Great Fire of London, The Invisible Order, Book Two: The Fire King picks up right where Rise of the Darklings left off, weaving adventure, history, and legend into a thrilling, heart-stopping story.