She's a vampire,
He's a wolf.

His mission is to avoid the two moons to join together.
Her mission is to terminate the wolves

What if they fall in love with each other? What will happen if the two moons collide? 

-- 

Kris aka The King
He's the king of the wolves pack. He's the responsible for keeping the pack safe.

Chanyeol aka The Prince
He's a wolf but a school boy. The king let him study to know how people live. The others know him for being the "Rulebreaker" of the pack.

Wolf Pack

Dara

She's one the vampires who kill wolves. She's already 53 years old, too young to be the Vampire's Princess. Her age was too old for her face because they're immortals. They can only be killed by the fire or being stabbed in their chest.

Chaerin aka CL
The vampires' queen. She's Dara's sister. She was the one who keep the moon of the vampires. He know Kris, wolves' king, for a very long time as her enemy.