Completely standalone episode with different ,new characters but it was such a good watch. The animation here was top-notch! It had rustic, spooky artstyle and visually felt like it was of Manga! There was no comedies, just solving a mystery about alien species and the tragedy it caused in the town. I felt like I was watching a murder mystery solving series. It might be a filler episode, but recommended to give it a try! Worth watching...