Father Thames

the long version

"Rebellious teen Jemima Mallard has done the unthinkable. She's joined the Youth Police Department (YPD). Is she serious, or is she spying for the criminal Father Thames? Fellow YPD officer Nick Mallard isn't sure. Before he can test her loyalty, the two must go to war. Their city is under attack. From the Thames Barrier Reef to the Sink estates, strange ships have breached the defenses. London hasn't seen anything like these raiders - adults and kids sailing and working together. But orders are orders, Jem must find find a way to stop them"--