Episode 1130 of "Detektiv Conan" begins with Genta, Ayumi, Mitsuhiko, and Haibara discussing a movie they recently watched. The children are especially excited about an upcoming concert by the band Knight Hearts, which is currently very successful.

The scene shifts to a restaurant where Professor Agasa, Conan, and the Detective Boys are eating. They notice some familiar faces, including Kobayashi-sensei, Detective Chiba, and Taiko Meijin, who appear to be on a date. The children speculate about possible romantic relationships among the adults.

Suddenly, the power goes out for a short time. Meanwhile, a group of women—Tokumi, Sumika, Mao, and Yasuko—are enjoying a night out together. Yasuko, a waitress, brings a dessert called Maritozzi, which the women eagerly try. But suddenly, Tokumi collapses and dies from cyanide poisoning.

Detective Chiba and Inspector Shiratori, who happen to be on the scene, immediately begin their investigation. It quickly becomes clear that the poison was likely administered through the dessert. Suspicion falls on Yasuko, Sumika, and Mao, as each of them had some contact with the dessert plate. Despite intense questioning, there is no clear suspect, and the investigation goes in circles.

Meanwhile, the Detective Boys, particularly Haibara, express their frustration over the slow progress and speculate about the romantic entanglements of the adults, adding a humorous and complex layer to the situation.

By the end of the episode, the detectives continue their search for the truth behind Tokumi’s death, setting the stage for the next episode.