There is a club on Vampire Lands called Club Sitim (Thirst). Its owners created it to give Humans a place to go if they want to willingly sell their blood to Vampires. They essentially become living donors for the Vampire(s) of their choosing. The Vampires are not allowed to kill, only to drink.

In a world where Vampires and Humans are struggling to co-exist peacefully, Cate visits Sitim for the first time with her friend Nirmani to try and make some money. But Cate gets more than she expected when she meets JiYong.