The Knights Templar was the most powerful, wealthy and mysterious military order of the Middle Ages, with its members entrusted with protecting Christianity’s most prized relic – the Holy Grail – and harboring secrets capable of great destruction. 'Knightfall' delves into the clandestine world of this legendary brotherhood of warrior monks. From their battles in the Holy Land, to their complex relationship with the King of France, to the betrayal that would ultimately lead to their tragic dissolution, the story of the Knights Templar has never been fully told until now.

Inspector John Marlott investigates a series of crimes in 19th Century London, which may have been committed by a scientist intent on re-animating the dead.