An exciting adventure series from Carnegie Medal winner Katya Balen, author of October, October and The Light in Everything.

Clem, Ash, and Zara are the Thames and Tide Club, weekend mudlarkers on the hunt for hidden treasures along the riverbank. Clem has found all sorts of things! Until one day, she discovers something magical that must be returned to the river… or else.

Before they know it, the friends are swept into a wild, underwater adventure to save Underwater London!

A story of mystery, friendship, and a splash of magic.