Jongin and Sehun were twins, born 4 minutes apart. Although they were born together, the two were nothing alike. Jongin was strong and loud mouthed; always bravely sticking up for the weak. Sehun was the opposite. The blonde male was quiet and stern, but always ready with a comforting smile for those who needed it. Together, they made up the most contrasting and compatible pair in the entire town.

One day, a fire broke out in the village, reducing a shed to ashes. Among the ruins was Sehun's blackened corpse. He had been killed, not by the burning infernos, but by the jealous town boys who envied the attention and power that Sehun had. They had brutally murdered him and set fire to his body to hide their tracks. It was a gruesome and horrible act, but the perpetrators were not punished for it.

Enraged, Jongin sought revenge on his beloved brother's killers. Enlisting the help of Sehun's psychic boyfriend, Kyungsoo, he contacted Sehun and allowed him to possess his body every time a full moon appeared. Every full moon, Sehun was revived. Every full moon, one of the town boys disappeared, only to be found bloody, charred, and dead the morning after.

Something is wrong, though. Even when Jongin told himself that he would respect Sehun and only work towards his goal for revenge, his heart is starting to disobey him. Its starting to yearn for the one person Jongin will not allow it to yearn for: Do Kyungsoo. Sehun's beloved.

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Do Kyungsoo, teenage psychic, has been shunned by everyone in his life for his powers. The only person he actually felt close to was Kim Sehun, the gentle boy that defended him from his bullies and even shielded Kyungsoo with his own body. After Sehun is murdered, his ghost haunts Kyungsoo, trying to make him see something. A message.

When Kyungsoo meets Sehun's twin brother, Jongin, everything becomes clear. The thing that Sehun so desperately tried to contact him about, the thing that he so craves...is revenge.

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Hearing rumors of a serial killer, renowned psychologist Luhan visited the small town in Gwangju. Little did he expect to find two boys and an enraged ghost at the root of the trouble. Instead of turning in Jongin and Kyungsoo while labeling them as insane killers, Dr. Luhan takes them under his wing and teaches them how to  "properly" kill. How to really avenge the death of their loved one.

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Jongin loved Sehun as if he were his own soul and Sehun loved his brother the same way. Death would not break their bond. No.

Death could not break their bond. Jongin wouldn't let that happen.

~

Sehun protected Kyungsoo. That was one of the main reasons he was killed. Because he harboured a monster. Now, Kyungsoo will protect Sehun.

He will become the monster he was so afraid of being called.