Dr. William Masters runs a successful medical practice and conducts a secret study of human sexuality; a former nightclub singer proves to be an asset to Masters' work.
Mycroft asks Sherlock to move to London, but before deciding whether to stay or go Sherlock has one last case to investigate. The genius sleuth looks into the murder of a beautiful young woman.
Elizabeth must negotiate with Iran regarding its escalating nuclear program; Jason interviews his father for a school report.
Elizabeth and cabinet members brace themselves as President Dalton prepares for a retaliatory nuclear attack on a country that has reportedly just launched missiles bound for the U.S.
Elizabeth attends a summit in Montreal to resolve territorial claims on the North Pole. An activist group detonates a bomb. Elizabeth learns that Russia was involved in the bombing. Henry helps one of his students work through a difficult decision.