In a bustling modern city, Yuna, a seemingly ordinary college student, begins to notice strange events — shadows that move on their own, whispers only she can hear, and glowing marks on her wrist. Unknown to her, she’s the last heir of the "Starlight Guardians", an ancient order protecting the boundary between reality and dreams. Her life turns upside down when she meets Jae-min, a mysterious transfer student who hides a dangerous secret: he belongs to the Shadow Clan, sworn enemies of the Guardians. But instead of hating her, Jae-min is drawn to Yuna — torn between his duty to destroy her and his heart that refuses to let go. As they slowly fall for each other, Yuna must decide: embrace her destiny and fight against Jae-min’s world, or risk everything to rewrite fate together.