When seventeen-year-old Spark takes a summer job working at a secluded house in England, organizing journals that span centuries and all written in the same hand, she discovers her true connection to the people who live there and the trait that makes them unique.

While sinister Lord Luxon makes himself at home in twenty-first century Manhattan, Peter and Kate, aided by Gideon, pursue The Tar Man through the streets of eighteenth-century London, when history is at its tipping point.