Further down, at the bottom of the cliff, they can see the river rushing over rocks. Police divers are called in. They find the body of Keisuke Sonoda in the river. The cause of death is blunt force trauma to the head, consistent with a fall from the cliff. However, there are also traces of sleeping pills in his stomach.
She provides a photograph of her husband—a handsome man in his early thirties with a confident smile. She also mentions that he was wearing a distinctive silver locket around his neck, which he never took off. Inside the locket is a small, old photograph of a young girl, not her. When Kogoro asks about this, Yukie looks down sadly and says, "He never told me who she was. He said it was a memento of a promise he made a long time ago."
Kogoro (via Conan) reveals that the locket is the key piece of evidence. It is not at the crime scene, and when the police search Yukie’s house, they will find it hidden in her jewelry box. Inside, besides Miyuki’s photo, there will be Keisuke’s fingerprints and, more importantly, traces of the sleeping pills from his system that transferred onto the locket when she removed it from his neck. Detective Conan Episode 406
However, the locket Keisuke always wore did not contain a picture of a childhood sweetheart—it contained a picture of , the girl he killed. He wore it as a constant reminder of his guilt, a promise to himself to never forget the life he took and to live honorably.
Kogoro inspects the car. There are no signs of a struggle—no blood, no torn fabric. The keys are still in the ignition. In the back seat, they find a briefcase containing architectural blueprints and a lunchbox that has begun to spoil. However, something is missing: the silver locket. Yukie had specifically mentioned it, but it’s not in the car or on the ground around it. Further down, at the bottom of the cliff,
She arrived at the shrine before him (using a different route) and waited. When he arrived, groggy, she confronted him about the locket. In his drugged state, he confessed and begged for forgiveness. She then pushed him toward the cliff. He stumbled, fell, and hit his head on a rock, then rolled into the river.
Suddenly, the doorbell rings. Ran rushes to answer, hoping for a client. A well-dressed, distressed woman in her late twenties stands at the door. She introduces herself as . She explains that her husband, Keisuke Sonoda , a successful architect, has been missing for three days. She has already contacted the police, but since there’s no evidence of a crime, they have only issued a missing person notice and are not actively investigating. Desperate, she has come to the famous "Sleeping Kogoro" for help. The cause of death is blunt force trauma
This episode is an anime-original story (filler) that aired on June 13, 2005. It is a single-episode case featuring Conan, Ran, and Kogoro Mouri. Opening Scene: The Afternoon at the Mouri Detective Agency