All his life, Jack Henley has felt at home in the woods, more at home than when he's actually at home with his parents. He loves watching the badgers play-fighting in the summer evenings, and pretending to be outlaws or cannibals with his two best friends. But when Jack discovers the most incredible secret of all, a beautiful, extraordinary, unicorn, he cannot believe his eyes.
He and the owner of the woods, Mr Finistaire, embark on a journey to save the unicorn from extinction. But as they continue in secrecy, Jack begins to wonder whether all is what it seems, or whether there is an ulterior motive to Mr Finistaire's interest... Will the bond between Keras and Jack be enough to withstand the danger that awaits them both?