Sand is the story of a young girl, Willy Cameron, her horse named Sand, and her involvement with therapeutic riding. The novel begins when Willy is involved in a serious car accident and is paralyzed from the waist down. After the doctors tell her that she may never walk again, Willy becomes extremely depressed and self-pitying. Then when she is going (unwillingly) for physiotherapy, she meets a young boy, Ben, who is involved in therapeutic horseback riding for his juvenile arthritis, and he persuades her to give it a try. The therapy with the riding gives Willy back the partial use of her legs. While still recovering, she takes on the training of Sand, a spirited rescue horse at the stable who was injured, and now spooks easily. The story expands at this point when her friend, Ben, becomes depressed about his relationship with his father, becomes involved in drugs, and disappears after going on a bad drug trip. Willy believes she knows where he is hiding, but has no means of transportation and, against the orders of the riding master, she secretly takes Sand from the stable to try and find her friend. But Ben is not in his right mind, and Sand is easily spooked. The fate of Willy, Ben and Sand all depends on what happens next.