In a resilient Edo-period Japan, Shogun Yoshimune Tokugawa, also known as Nobu, grapples with age-old customs that defy logic in her eyes. Amidst a male-exclusive epidemic despite men being a minority, the Oooku houses three thousand alluring young men. Seeking to understand the matriarchal society's roots and the enigmatic disease, Nobu delves into historical records. Adaptations to accommodate the plague have reshaped traditions, drawing eerie parallels to the tale of the first female shogun, Iemitsu Tokugawa. Central to these changes is the pivotal role of Arikoto Madenokoji, a former monk whose fate intertwines with the shogun and her Inner Chambers.