"Intrigue in the Bakumatsu - Irohanihoheto" is a historical fantasy anime set during Japan's Bakumatsu period, a time of political upheaval and transition from the Tokugawa shogunate to the Meiji Restoration. The story intertwines historical events with supernatural elements, focusing on a mysterious traveling theater troupe and their encounters with a cursed relic known as the "Eirei Kakka." This artifact is said to hold immense power and is sought after by various factions, each with their own motives.

The protagonist, Yojiro Akizuki, is a skilled swordsman and former assassin who becomes entangled in the quest for the Eirei Kakka. He is driven by a personal vendetta against the relic, as it is connected to the death of his father. Yojiro crosses paths with the theater troupe led by the enigmatic Kotoha, who possesses a deep knowledge of the relic and its history. Together, they navigate a complex web of alliances and betrayals involving samurai, revolutionaries, and supernatural entities.

The narrative explores themes of loyalty, revenge, and the clash between tradition and modernity. Key historical figures and events are woven into the plot, grounding the fantastical elements in a recognizable historical context. The series balances action, intrigue, and character development, with a focus on the moral ambiguities of the era. The Eirei Kakka serves as a central plot device, driving the motivations of the characters and the progression of the story.

Supporting characters include members of the theater troupe, such as the spirited performer Yuki and the stoic warrior Shiranui, as well as historical figures like Sakamoto Ryoma, who plays a pivotal role in the political landscape. The antagonists range from rival factions seeking the relic's power to supernatural beings tied to its curse. The interplay between these characters creates a dynamic and engaging narrative, blending historical drama with supernatural intrigue.