Shadowplay: Part 1 (S04E11)

A young woman with psychiatric problems has killed her family through an arson attack on her family's home. She claims she was incited to do this by a mysterious figure known only as "The Shepherd." It transpires that two other women with mental illnesses claimed they were incited to commit murder by the same person in the past. The team needs to discover if this is a journey through the imagination or reality. (iTunes)