For years, John Cardinal's wife, Catherine, has battled severe depression. People are saddened when she finally takes her own life, but they are not really surprised. Cardinal, of course, is devastated. Despite the suicide note in Catherine's own handwriting and the coroner's finding that there is no evidence of foul play, Cardinal cannot bring himself to believe that Catherine has really killed herself. When hateful notes about his wife's death begin to arrive in the mail, he begins to suspect murder - perhaps revenge from one of the many criminals he has put away over the years. But because the police have not opened a case, he is forced to investigate on his own. Even his longtime colleague Lise Delorme can't help him - she's wrapped up in a nasty case of her own.