Detective Conan Episode 487 Info

Need to verify the exact plot of episode 487. Since I can't look it up, I'll rely on general knowledge. The Sherlock Holmes arc has multiple episodes where the students play roles, and there are multiple cases. The specific case in episode 487 could be about a locked-room murder or something similar. The culprit might use a clever trick, only to be caught by Conan's attention to detail.