Nathan and his sister Lennie are on holiday in Greece with their parents.

Nathan finds a small Colossus figure, which legends tell him is made from the melted-down metal of the great Colossus of Rhodes.

He feels it brings him luck. When he subsequently loses it, he is bereft, but a local boy he meets, Stefan, helps him to find it again.

Stefan then encourages him to complete a series of daring feats, including an epic swim across the harbour.

Although Nathan doesn't know it, Stefan is putting him through three mythical tests.

The blend of mythology and adventure leads to an uplifting ending, with the overall message that we can all make our own luck.

Lesley Howarth has won the Smarties Book Prize and the Guardian Children's Fiction Award.

Her first novel was shortlisted for the Whitbread Award.