Tom and Hester's daughter, Wren, longs to escape the peace of static Anchorage. She craves the dangerous adventures her parents once had - and a charming submarine pirate is ready to take her to sea. But the mysterious object that she steals for him ignites a conflict that will tear the whole world apart...

"No 11-to-16-year-old should miss the superbly imagined debut novel from Philip Reeve" - The Times

"This big, brave, brilliant book combines a thrilling adventure story with endless moral conundrums" - The Guardian