Leon is a small-time crook who's ridden his luck for three decades. When he starts splashing big money around, the cops are desperate to know where it came from. They call in Cherub, a secret organisation with one essential advantage: even experienced criminals never suspect that children are spying on them.

James' latest mission looks routine, but the plot he begins to unravel isn't what anyone expected. And the only person who might know the truth is a reclusive 18-year-old boy. There's just one problem. The boy fell to his death 13 months earlier.