Like Minds (2006) on Netflix

Plot summary

Sally Rowe, a forensic psychologist, is asked to assess seventeen-year-old Alex Forbes after he is taken into custody at a railway station with the body of his classmate Nigel Colbie and powder on his hand. Alex describes his years at boarding school, where Nigel kept to himself, studied taxidermy and talked about death. Nigel claimed that he and Alex were descended from the Knights Templar and drew him toward a secret society he called the Brotherhood, which he said had a sacred purpose for the two of them. The police treat the death as Alex's doing, and Rowe has to weigh the boy's account before a charge can be laid.