"Kagerō no Tsuji - Inemuri Iwane" is a historical manga set in Japan's Edo period, blending elements of mystery, action, and drama. The narrative centers on Iwane Sakazaki, a ronin (masterless samurai) who serves as a yoriki, or assistant magistrate, under the command of Magistrate Toyama no Kinshiro. Despite his reputation as a lazy and perpetually sleepy individual, Iwane possesses exceptional swordsmanship and a sharp intellect, which he employs to solve complex cases and bring criminals to justice.

The series unfolds through episodic cases, each presenting a new mystery or crime that Iwane must unravel. His unassuming demeanor often leads others to underestimate him, but his keen observational skills and strategic thinking allow him to outwit adversaries and uncover the truth. The cases frequently involve corrupt officials, rival factions, and intricate schemes, reflecting the political and social tensions of the Edo period. Iwane's interactions with other characters, including his superior Toyama and various townspeople, add depth to the narrative, showcasing his loyalty, sense of justice, and occasional dry humor.

The manga delves into themes of morality, justice, and the complexities of human nature, often blurring the lines between right and wrong. Iwane's past is gradually revealed, providing insight into his motivations and the events that shaped his character. The historical setting is meticulously depicted, with attention to period-accurate details in architecture, clothing, and societal norms, enhancing the immersive quality of the story.

Through its blend of action, mystery, and historical context, "Kagerō no Tsuji - Inemuri Iwane" offers a compelling exploration of life in feudal Japan, driven by a protagonist whose unorthodox methods and hidden talents make him a unique and memorable figure in the genre.