Okay, so the castle they go to near the end of the series: I've been there in real life lol. It's an actual castle (name: Schloss Neuschwanstein in Germany) and so I laughed when I saw the one part where Hyungwoo is looking out the window and down at his dad because it's not possible to do that at the actual castle. The bedrooms are no where near where his dad wouldve stopped his car, so I was laughing and saying "yea doesn't make sense but it's a story so whatever"
Sweet Man