Following the success of the Shinobi-no-Mono series, Daiei Studios created one of the finest 1960s black-and-white ninja films in a year largely filled with color. Issei Mori directs Hiroki Matsukata as the reluctant leader of a small team of spies tasked with kidnapping a noblewoman from a heavily fortified castle. As darkness falls, the loyalty of the ninja shines through as they navigate a world of mystery. The mission takes a dark and fatalistic turn in this noir-influenced film, marking a high point for both the decade and its distinctive ninja cinema style with Mission Iron Castle.