One of the best Mystery/Thriller K-dramas out there. The pacing is slow and sometimes agonizing, but the show truly communicates the hopelessness and fear the OP fears from his neighbors and ultimately the main antagonist. The show tells the story of a university student who rents out a very cheap apartment in hopes of saving money, but his neighbors make life very hard for them. Each of the neighbors has a unique personality and special kind of dysfunction that would make you think twice about whether the cheap rent is worth it. Def worth a watch. You will not regret it. Soundtrack is pretty amazing too.