The girl who lost her shadow / Emily Ilett.

"Gail was eating cornflakes when her shadow disappeared. She wasn't surprised. Everything was falling apart and it was all Kay's fault. Gail used to be close to her big sister. But lately Kay had changed: she's sad and quiet, and Gail has no idea how to help. But when Kay's shadow slips away as well, Gail knows she must bring the shadows back. Gathering her courage, Gail chases the shadows through caves and forests, discovering maps, a pearl and an unexpected new friend who can speak to birds. Can she find what the shadows are seeking?"--Provided by publisher.