"D-Cup Hunter" is a manga series that blends elements of comedy, action, and ecchi genres. The protagonist, Kakeru Shiki, is a young man with a unique ability: he can detect and locate women with D-cup bust sizes using a special radar. This ability stems from a mysterious power he gained after a childhood encounter with a supernatural entity. Kakeru uses his talent to assist a private detective agency run by his childhood friend, Ririko Nanase, who is also a skilled martial artist. Together, they take on cases that often involve tracking down individuals or solving mysteries, with Kakeru's ability frequently playing a pivotal role.

The narrative revolves around episodic cases, each introducing new characters and scenarios. Kakeru's radar often leads him into humorous and precarious situations, as his ability attracts both admiration and trouble. The series balances its comedic tone with moments of action and lighthearted drama, particularly in the interactions between Kakeru and Ririko. Their dynamic is central to the story, with Ririko often serving as the voice of reason and providing the muscle when situations escalate.

Supporting characters include a variety of clients and adversaries, many of whom are women with D-cup bust sizes, tying into the series' central theme. The manga occasionally delves into the origins of Kakeru's power and explores the consequences of his unique ability, adding depth to the otherwise comedic premise. While the series leans heavily into its ecchi elements, it maintains a focus on the detective agency's missions and the camaraderie between its members. The episodic structure allows for a mix of standalone stories and ongoing character development, creating a balance between humor, action, and occasional heartfelt moments.