Jun-ho, a vampire living in the human world as a college student, once broke a clan rule 10 years ago and now faces the threat of disappearing. His only hope of survival is to drink the blood of a pure-blooded human and become human himself. At that moment, the freshman Min-hyun, a pure-blooded human, appears before him. Seeing his chance, Jun-ho approaches Min-hyun... but things don’t go as expected.

Jun-ho tries to get closer to Min-hyun by suggesting they work on a university assignment together. As they spend more time together, Jun-ho finds himself increasingly drawn to Min-hyun’s adorable appearance and pure heart.

Jun-ho invites Min-hyun to his secret hideout on campus. Originally intending to win Min-hyun’s heart to drink his blood, Jun-ho makes his move. Just then, Min-hyun’s protective older brother shows up and interrupts them.

Min-hyun learns that Jun-ho is a vampire targeting his blood. At the same time, he begins to realize his own feelings. Meanwhile, Jun-ho hesitates to go through with his plan, leading to miscommunication between them. Then Hae-su, someone who knows Jun-ho’s past, appears.

Hae-su reappears in Jun-ho’s life after ten years. He proposes that the two of them drink Min-hyun’s blood together and become human. Min-hyun becomes uneasy about Hae-su’s presence, and the truth behind the incident from 10 years ago comes to light.

As the time of his disappearance draws near, Jun-ho grows weaker. He rejects Hae-su’s offer and coldly pushes him away. Driven by jealousy, Hae-su impersonates Jun-ho and lures Min-hyun to the rooftop.

Sensing that Min-hyun is in danger, Jun-ho rushes to the rooftop just in time to save him. The two confront each other, sharing their feelings and trying to reach a resolution together.

Jun-ho and Min-hyun affirm their love for each other. But their joy is short-lived, as Jun-ho’s time is running out. What future and dreams will the two choose together?