Dragon Shield: The City of Beasts: Book 3 by Charlie Fletcher
New allies and new hope leave siblings Will and Jo ready to face the dark force that lurks in the British Museum. It has frozen London, leaving the life force of the city's inhabitants to drain away. But with nearly all the animal statues of London and a nest of dragons against them, will they be able to save their mum - and the world - before time runs out?
With beautiful illustrations by Nick Tankard.