Possessed people.

I must say that I'm enjoying this! That scene at the roof was really creepy. The supporting actor was great! I was wondering how a detective would be part of this exorcism scenario but I guess she will believe it later. It's funny to watch her reactions of this supernatural thing hahaha and her friendship with her sunbae is hilarious in a way. That last scene was very emotional and the OST ah! really suited the situation.
Can't wait to watch more.