Lost Days (2014)

suspense, fragile relationships, creeps and murder. Both dramas are quite short; Shotenin Michiru is better imo.

A group of students are stuck in a situation & they all get to know everyone's true selves. In LB, the main leads are stuck in one of the friend's resort home. While WC the main characters are stuck in their school.

Has many episodes with similar settings; stuck in a villa during snowstorm with a murderer lurking among the visitors

Both dramas share the same feeling. Students are isolated from the outside world and one of them is a psycopath.