After spending ten years in a temple in the mountains, Jūzō, a deadly ninja, is ordered to do one last job: to kill the most powerful man in the country, the Taiko Toyotomi Hideyoshi. To achieve this, he must infiltrate the impregnable fortress that Hideyoshi has just built: the Fushimi castle. On his return to Kyōto, the capital of the empire, he will reunite his former companions, survivors of the massacre of Iga who, like him, are living hidden, to help him in his mission. The climate in the capital is very tense, political intrigues are the order of the day and nothing is what it seems, reason why you can not trust anyone to develop the plan that allows you to carry out your mission. In addition, to achieve his goal, Jūzō must overcome two almost insurmountable obstacles: Gohei, his inseparable childhood friend, who in the service of the shogun has the order to capture the conspirators; and Kohagi, a ninja woman whose true intentions she does not know. Thus begins a story of friendship, camaraderie, love, passion, honor and death battles; an epic novel that will please both fans of history and fans of adventure novels. The owl castle (Fukuro no shiro) is the most famous ninja novel in Japan. Winner of the Naoki prize in 1960 has been adapted twice (1963 and 1999) for the big screen.