A unicorn, protector of her forest and its animals, comes to wonder why she has not seen others like herself. When word reaches her that the others were captured a long time ago by the Red Bull and his mysterious master, the unicorn sets out on a quest to find the rest of her kind. With they help of her friends, the magician Schmendrick and the world-weary Molly, they journey across a land of magic and danger to a distant prison that holds all of unicorn-kind.