In the twilight of a mysterious childhood full of wonder, Billy Argo, boy detective, is broken-hearted to find that his younger sister and crime-solving partner, Caroline, has committed suicide. Ten years later, Billy, age 30, returns from an extended stay at St Vitus' Hospital for the mentally ill to discover the world full of unimaginable strangeness. Billy finds the companionship of two lonely, extraordinary children and, with a nearly forgotten bravery, he falls in love and confronts the nearly impossible solution to the mystery of his sister's death.