In the darkness of the night, when the light of the sun no longer shines, the immortal creature hidden among men will rise up with his red eyes to prey on them with his deceit. Humans would be easily seduced by it and become easy prey. Centuries of warfare ensued between the creatures that ruled this land until a treaty was formed and since then the immortals could no longer freely hunt humans. However, their strong instinct for human blood still made some of them break the treaty. The immortal elder who led them all had to intervene, so a team was formed to eradicate those who broke the treaty, "The Twilight". Karl Griffin is the leader of The Twilight since 500 years ago after several generations of The Twilight's leadership. Karl, has no memories of the past when he was a human and he wants to regain his lost memories because he feels something in him is missing and makes him empty. Dean Dominic, an orphan who works as a model who is no longer selling and continues to struggle to live. Dean had a golden age as a model when he was young but as he grew older and his body became more masculine, his modelling life declined while his uncle who depended on him for his livelihood continued to make trouble and complicate his life even more. An encounter between a vampire and a human happens in a corner of the city that ends up changing the story of both of their lives. Past lives come to light and the long journey of their lives begins with the ups and downs of the relationship and together they overcome the obstacles.

A system was created with incredible technology by scientists over many years. After its completion, the system was used for military purposes. However, after a while the system began to lose control and not only took people who were entered into the system for military training, but the system instead pulled people randomly causing chaos outside the system because many ordinary people suddenly disappeared into the system. Ian, a 25-year-old young man was suddenly pulled into the system along with his cousin and uncle while they were in the hospital. Ian, who had been in the hospital for almost 8 months, was finally able to get out but he was pulled by the system. But who would have thought, Ian as a new examinee in the system even has a past with the system that is so deep. His attitude as an examinee is also extraordinary, unlike other examinees. Ian was nicknamed the number one student who always challenged the system. On the other hand, Ian met Alan, examiner A001 who became the examiner responsible for Ian and the examiner who had a hot and cold relationship with him. Time after time, problem after problem, and exam after exam passed. Ian and Alan's relationship is changing, past cases are revealed and together the two of them want to destroy the system that has been out of control and its proper function.