Thirteen-year-old Kat discovers a whole new level of being in trouble when she and her motor-mouthed foster brother, Ned, sneak into a neighbour’s garden and find themselves in 1670 London just after the Great Fire and the Black Death. Conman Scardsale can’t believe his luck when the two children, wearing strange clothes and shoes of wheels and multi-colour lights, appear in his brother’s house. The children provide him and his mean dog, Mr Growler, with meat pies aplenty as he sets them to work in the city’s coffee shops where they win many admirers including King Charles II and Samuel Pepys, who is outraged to learn they’ve been reading his diary. It’s a race against time as Kat and Ned try and escape the clutches of Scarsdale and the vile Mr Growler, with the help of half a dozen monkeys. Will they stay trapped in the 17th century forever or will they get back to their own time?