Harry Saxon becomes Prime Minister of Britain and his reign of terror begins. The Doctor, Martha, and Jack begin to unravel his true identity and a plot to destroy the Earth that stretches to the end of time.
The Duke of Holdernesses' son is kidnapped from his preparatory school, the Priory School. With the Duke determined to avoid publicity, Sherlock Holmes is called in, to investigate one of the most complex cases of his career.
