Episode 487, titled "The Final Problem, Sherlock Holmes - Case.13: The Final Episode - Part 1," is part of the larger Sherlock Holmes arc, which reimagines the characters and themes of Doyle's tales in a Japanese school setting. The episode begins with a mysterious invitation to a "Sherlock Holmes" themed party hosted by Professor Mori, a local reclusive genius with a fondness for Holmesian mysteries. Among the attendees are students role-playing as Holmes (Conan), Watson (Ai Haibara), Moriarty (Dr. Agasa), and others. During the event, a series of enigmatic murders unfold, modeled after the Holmes canon. A "murder" occurs in a locked room, with no apparent escape or entry point for the perpetrator—a classic "locked-room mystery" trope.