Two hundred years ago, in the world of Fireworld, lived Taemin and Juchan. They lived as vampires. They were inseparable friends, but their bond began to fray when a human girl suddenly appeared before Taemin. Taemin fell in love for the first time with a human girl named Choi Eunsu. However, Juchan, who couldn't stand seeing a vampire fall in love with a human, ended up killing Eunsu. Taemin, realizing this too late, vows revenge against Juchan and keeps the deceased Eunsu preciously in his secret room. Taemin lived a wandering life for 200 years, and then he coincidentally encounters Choi Eunseo. Eunseo went into the forest to keep a dangerous bet with her friend Wonwoo, but to Taemin, it was as if a human who looked exactly like his first love, Eunsu, had appeared before him after 200 years. Drawn even more to Eunseo because she even smelled like sweet blood, Taemin impulsively decides to make her his bride. Eunseo, trying to escape, eventually falls in love with him. Juchan tries to interfere between them. Their heartbreaking romance begins.