The plan was to wait for a windy day before the Gion festival and set fire to the Kyoto Imperial Palace, and in the ensuing confusion confining Prince Asahiko NAKAGAWANOMIYA (who became Asahiko KUNINOMIYA later), assassinate Yoshinobu HITOTSUBASHI (Yoshinobu TUGAWA) and Katamori MATSUDAIRA of the Aizu clan, and take Emperor Koumyou to Choshu.
計画は、祇園祭の前の風の強い日を狙って京都御所に火を放ち、その混乱に乗じて中川宮朝彦親王（後の久邇宮朝彦親王）を幽閉し、一橋慶喜（徳川慶喜）・会津の松平容保らを暗殺し、孝明天皇を長州へ連れ去るという物であった。