Harper and the sea of secrets - Cerrie Burnell

The Songs of the Sea festival is about to start, but disaster has
struck! The royal musicians will be performing, but all their instruments
have disappeared...
Harper and her friends use her flying umbrella to come to the rescue,
and that very night they start hearing beautiful music coming
from Melody Bay. Will they have the courage to walk along the pitch-black
smugglers' tunnels passing under the sea to find out who
has stolen the instruments?
A captivating adventure story all about friendship, creatures of
the sea and magic.