In eighteenth-century London, twelve-year-old linkboy Philo Grey has spent most of his childhood out on the streets, collecting information to sell. One of his best customers, Mr Bishop, pays him good money for intelligence about the Jacobites, who are plotting to overthrow King George. But spying on the Jacobites is a dangerous business – especially when Philo becomes the target of a rival gang of linkboys. And then there’s Philo’s old master, Garnet Hooke, who’s never forgiven Philo for leaving him. Garnet feels so betrayed, he’ll stop at nothing.
Luckily, Philo has friends as well as enemies. He can trust his crew of linkboys, his team of informants, and his staunch friend Nathaniel Paxton, a surgeon with a background in espionage. Even his new friend, actress and master of disguise, Caroline Cowley, is a valuable ally. But with his enemies closing in, Philo has to ask himself: where should his loyalties really lie? And how far should they take him?