The body of a young student, Alys Thomas, is found at the exact centre of a vast expanse of marshlands by two young boys. She is dressed immaculately in a scarlet dress and seems to have been deliberately placed there. Mathias, struggling with his own demons from the past becomes more emotionally connected to the case than is wise, a fact not missed by his detective partner Mared and Chief Super Prosser. The story takes us from the Classics department of the university to the "Last Picture Show" loneliness of an isolated train station; from broken ex-policemen to modern day horse rustlers. With professional and personal loyalties pushed to the limit, Mathias finds himself on an emotional knife-edge. What price solving a case if he himself ends up with blood on his hands? Is the case at the children's home from the first episode really closed? More questions than answers in an explosive series finale as a haunted and blood spattered Mathias walks alone into the wilderness.