Ignored by his father and sent to Derbyshire for the weekend, twelve-year-old Peter and his new friend, Kate, are accidentally transported back in time to 1763 England where they are befriended by a reformed cutpurse.
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.