Coming from a broken family, Jeon JungKook feels that he is alone and can't find anyone who understands his situation. During a visit at his father's house, JungKook meets his soon-to-be step brother, who he wasn't aware of before. JungKook's relationship with his step brother soon started to develop. Soon, they managed to consider each other close. Maybe too close. JungKook's step brother has skeletons in his closet, that he desperately wants to clean out. Turns out, he isn't the only one with secrets. One decision made for a series of events to follow soon after, none were good. Can they ride this out together or will they have a fall out?

After a gruesome murder, JungKook and Jimin struggle to keep the tragic death a secret, along with a secret relationship. Because of high tension, everyone seems suspicious, even Jimin's half brother, Kim Ji-won, who is slowly becoming a part of their lives. Although JungKook's crew are skeptical about Ji-won, JungKook defends him and sticks by his side. Suddenly, JungKook's crew consisting of: Choi, Suho, Namjoon, Jimin, Ji-won, Jackson and Hoseok, are slowly being picked off one by one. The killer is utterly invisible but knows their secrets. Tension grows even higher knowing that no one else should know about the murder or the secret relationship. Who is this invisible killer? Who is telling their secrets?