ご存知！旗本退屈男Ⅵ 伊達家に倒幕の陰謀！

Sawatari Shusui was told about 7,000 ryo of buried gold by Osuke, who claimed to be a princess of the Fujiwara family. Shusui speculates that powerful people in the Date family and the shogunate are planning to overthrow the shogunate using buried gold and gets excited about a major national crisis. He gets separated from Osuke due to interference but with the help of his sister Kikuji and others he tracks down Osuke's whereabouts. He then realizes that Osuke is not from the Fujiwara family but is actually the daughter of Edo elder Itakura Shōken who has been confined under the pretext of an epidemic disease. Having promised to help Osuke, Shusui goes up to Edo Castle and advises shogun Tsunayoshi not to visit Nikkō Tōshō-gū Shrine which has been restored by Date family because "evil spirits are attached". However, Tsunayoshi is furious and orders him to stay under house arrest.