Lengthy spoilers for those who can't wait

Basically the top (kim jinseob) is stupidly obsessed with his boss (taeyong) and he found out he has relations with that old guy. So he took photos from the button camera and blackmailed him. The top was a sadist and rough with Taeyong. He's so angry with him and honestly it's just pure bdsm sex.

Now he has a co-worker who accidentally found out what's happening. He saw them fucking in the car. He confronted Taeyong about it and offers to help him. While they're trying to gather evidence or whatever to free Taeyong from Jinseob, he found out that he has a history of violence and has a classmate (?) who also revealed the truth about Jinseob. Turns out he was his victim before too. So he gave Taeyong a flashdrive that possibly contains evidence.

Things happened, Teayong and his co-worker seems to be fuck buddies by now but Taeyong can't get it up or he can't be satisfied. He's becoming a masochist. He's finally got the courage to free himself from Jinseob and the two got in to an altercation. He let go of Taeyong and didn't bother him after that. Now that Taeyong's free, he now enjoys his freedom by having sex with whoevers available but since Jinseob turned him into a masochist he can't be satisfied unless it was him.

At the ending, he loses his mind and dances half naked at the middle of the dancefloor at a bar and he passed out. Next scene we saw him being carried by someone to Jinseob's apartment. He saw Jinseob waiting for him to wake up because apparently he doesn't want to live anymore, so attempted to hang himself in front of Taeyong. But Taeyong prevented it from happening because he can't be satisfied anymore if it's not Jinseob. The kissed and cried. The end.