"Detective Conan: The Culprit Hanzawa" is a spin-off manga series set in the same universe as "Detective Conan" (also known as "Case Closed"). The story takes place in Beika City and centers on a shadowy, nameless figure referred to as "Hanzawa," who represents the archetype of a criminal suspect often depicted in the original series. Hanzawa is characterized by a black silhouette with glowing white eyes, a design commonly used in "Detective Conan" to obscure the identity of culprits before their reveal. In this series, Hanzawa is personified as a distinct character navigating daily life while grappling with the constant suspicion and scrutiny that comes with his appearance.

The narrative explores Hanzawa's attempts to live a normal life despite his inherently suspicious demeanor. His interactions with the residents of Beika City often lead to misunderstandings, as his appearance and behavior frequently align with the traits of a typical criminal suspect. The series humorously subverts the tropes of the original "Detective Conan" by placing Hanzawa in situations where he is unjustly accused or mistaken for a criminal, even when he is innocent. The tone is comedic, with a focus on situational irony and satire, as Hanzawa's efforts to avoid suspicion often backfire, further cementing his reputation as a potential wrongdoer.

Key characters include Hanzawa himself, who serves as the protagonist, and various residents of Beika City who interact with him. The series occasionally features cameos or references to characters from the main "Detective Conan" series, such as Conan Edogawa and Kogoro Mouri, though they play minor roles. The humor often stems from the contrast between Hanzawa's earnest attempts to prove his innocence and the absurdity of the situations he finds himself in. The manga maintains a lighthearted approach, using its premise to parody the crime-solving genre while offering a fresh perspective on the world of "Detective Conan."