Ethan, an ordinary college student, was deeply in love with his vampire boyfriend Chris. However, he accidentally discovered Chris was having an affair with his own brother Blake. Blake publicly humiliated Ethan, mocking him as nothing but a low-grade Class C blood bag while boasting of his noble Class A blood.
Heartbroken, Ethan returned home. Just then, Leo, the supreme vampire king covered in wounds, broke in while fleeing werewolf hunters. By a strange twist of fate, Leo found that though Ethan seemed to have ordinary Class C blood, it was actually an extremely rare Class S blood.
Later, Chris and Blake intensified their bullying. Barnes, leader of the dark vampires and Chris' uncle, allied with werewolves and Chris to stage massacres and frame Leo, sparking a war between humans and vampires. Facing mortal danger, Ethan offered his special blood to empower Leo. The trap worked perfectly. All villains were defeated. Having gone through countless hardships, Ethan finally chose to stay by Leo's side.
