You never know what you'll find beneath the surface. Deep below the surface of the planet Adamantine lies a crystalline wonder world of lava seas and volcanic islands, home to living rock-people. But when the Doctor and her friends arrive on Adamantine they find it under threat.

Una McCormack is a New York Times bestselling author. She has written four Doctor Who novels: The King's Dragon and The Way through the Woods (featuring the Eleventh Doctor, Amy, and Rory); Royal Blood (featuring the Twelfth Doctor and Clara), and Molten Heart (featuring the Thirteenth Doctor, Yaz, Ryan and Graham). She is also the author of numerous audio dramas for Big Finish Productions.