The Secret relationship between Taeil and Donghyuck, a professor and a student is just a tragedy, which makes the relationship forbidden and complicated as well as breaks Taeil's marriage with his beloved husband, Jungwoo Kim.

When Jungwoo finds out about their secret including Donghyuck's unborn child in Taeil's womb, he decides to take revenge, as well as to get his husband back.

Jungwoo eventually encounters Mark, a wealthy young man, and Donghyuck's obsessive lover, studying in the same college as him. Mark offers Jungwoo to help him with the plan that Jungwoo avoids at first but goes ahead later. They further proceed with the plan together.

However, things start unrolling in unexpected ways when Jungwoo and Mark start falling for each other. That's how the four souls start searching for their final destination which was already their predestination.