Yuri is a high school student who has been starved of love his entire life. His adoptive parents only care about their biological son, and Yuri is constantly bullied at school. Despite his loneliness and pain, he hides it behind a bright and gentle personality — a “smiling depression” type who always puts others before himself. His true identity is the descendant of the werewolf bloodline.
Brian, the fallen heir of the vampire clan, has lived for centuries following his father’s strict belief: vampires must never drink human blood. That changes when his enemy shatters half of his heart with a single blow. Gravely injured, Brian falls into Yuri’s swimming pool in the human world — and is unexpectedly saved by Yuri’s blood.
At first, Brian is only drawn to Yuri because of his extraordinary blood. He secretly follows and observes him, while growing increasingly jealous and possessive toward Lucius, the werewolf who has always stayed by Yuri’s side. But the closer Brian gets to Yuri, the more he is moved by this fragile yet kind-hearted boy. What begins as a hunger for his blood slowly turns into genuine love.
Lucius, the young heir of the werewolf clan, was the only source of light in Yuri’s life before Brian appeared. Disguised as an ordinary high school student, Lucius has always protected and supported Yuri. As the star player and ace of the school football team, he is confident, charismatic, and admired by everyone. He takes every hit meant for Yuri and uses his warmth to thaw the coldness Yuri has carried inside. The relationship between the three is pushed to its breaking point through enemy attacks, betrayal, misunderstandings, and impossible choices.
The antagonist Aiden is obsessed with the secret of the “pure blood” left behind by Brian’s father. He sets traps and hunts Brian relentlessly, eventually leaving Brian severely injured. To save him, Yuri cuts his own wrist and feeds him his blood, unknowingly forming a blood bond between them.