For young Kathrine, a girl who appears to have everything going for her, friendship may be the one thing she will never find. So her father tells her, "If you really want a friend, be a friend." But even though she's smart, has a sense of humor and is the star of her soccer team, her search for a friend has been a long journey indeed. One that's taken her all the way to Misselthwaite Manor in England, where she is enduring her first stay with her sickly cousin, Margaret. After Katherine decides she needs to try harder at being a friend, she finds an old diary that leads to an unexpected adventure riddled with hidden passageways, a puzzling portrait and clues to a secret garden. Together, Katherine, Margaret and a boy named Timothy explore the mysteries of Misselthwaite and discover what it really means to be a friend.