Ryoji Renjo operates a small private detective agency in a bustling Japanese city, but the cases he accepts are far from the dangerous underworld of crime. Clients typically hire him to resolve trivial personal disputes, such as suspected infidelity or petty theft. Despite this mundane workload, Ryoji possesses an extraordinary and unexplained talent for gourmet cooking. When his investigations lead him into the kitchens of various restaurants and culinary establishments, every chef he encounters is mesmerized by his superior palate and profound understanding of food preparation. This hidden skill sets him apart from ordinary detectives and forms the core mystery of his character. A key element of the narrative is his unknown connection to the famous head chef of the prestigious Togawa restaurant, a relationship that the story gradually explores as it unfolds.

Ryoji is accompanied by Aoi, an outgoing and energetic woman who shares his deep passion for eating. She acts as his companion and助手, helping him navigate cases while enthusiastically participating in the culinary discoveries they make along the way. The series is set against the backdrop of Japan's urban culinary scene, with each investigation bringing the pair into contact with a variety of food-related professions and personalities.

The narrative follows an episodic structure as Ryoji and Aoi take on different cases. In each arc, Ryoji is hired for a seemingly straightforward investigation that intersects with the world of food. As he looks into these matters, he inevitably confronts a chef or food artisan whose work has become compromised, stagnant, or fraudulent. By applying his exceptional cooking skills and sensory knowledge, Ryoji does more than solve the mystery; he actively transforms the culinary landscape around him. His interventions revitalize struggling kitchens, expose culinary pretension, and inspire the cooks he meets to reach new levels of excellence. Throughout these adventures, the ongoing mystery of Ryoji's past and his specific ties to the Togawa restaurant provides a continuous thread, building toward revelations about why this detective hides such an extraordinary talent beneath his unassuming professional facade.