S01E261: The Fearful Legend of the Snowy Night (1)

Conan, Kogoro, and Ran are driving to a hot spring when the road gets closed due to snow, and so they accept an offer of staying the night at a nearby house. The next day they discover the body of the company president dead and when they follow the footprints, they find his eldest son dressed up in armor and also dead in a locked room.