The Sanada clan stands defiant as the Tokugawa forces close in on Ueda Castle during Japan's turbulent Sengoku period. When Hidetada Tokugawa arrives demanding that the castle open to him, the Sanada and their retainers have other ideas. Among them is Sarutobi Sasuke, found as a baby in a crater left by a falling meteor and raised into a master ninja under Sanada Nobushige, also known as Yukimura. Holding Ueda Castle with just 2,000 soldiers, the strategist Sanada Masayuki faces a Tokugawa army of 38,000, and Nobushige and his followers, Sasuke included, help the small garrison fight back hard. The one-episode special is set in the fifth year of the Keicho era, as the Tokugawa push to secure their hold over Japan.