When her parents send her to stay with a grandmother she hardly knows for the summer, Elen is furious. Gran lives on a tiny island and doesn\'t want her either - it\'s not an easy start. Gran\'s idea of childcare is to give Elen a map and tell her to explore. Who is the odd boy on the beach with a puffin? After saving Gran in a storm, Elen finds a picture that she\'s sure is a clue to hidden treasure. She investigates - and finds a very different treasure from the one she expected.