A young girl, Flo, befriends an old horse kept in the stables of her riding school. She learns that this horse, Augustus, was once a world champion show jumper but is now crippled and bitter. Is it Flo's imagination or is there always the same magpie somewhere near this horse? Little does she know that the two animals are lifelong friends who share a magical secret. Flo soon discovers that she is finding her way into more than simply the story of Augustus, the once-famous horse now nicknamed 'Peg Leg Gus'.

This is a story that touches on sadness and loss in a way that is often avoided in books for younger readers. It is a book about hope and love and how a girl's open heart transforms the bitter and wounded old horse.