Kou Yamori is an average middle school student who struggles with grasping the complex concept of love. Because he sees little sense in surrendering to the norm, he soon stops going to school. Plagued with insomnia due to his idleness, Kou begins roaming the lonesome streets at night. One night, Kou encounters a bizarre girl named Nazuna Nanakusa who believes that people stay awake during the night because they are dissatisfied with how they spent their day and cannot rest until they release their inhibitions. Nazuna offers to help Kou with his sleep issues and invites him over to her place, where she convinces him to share a futon with her. Feeling uncomfortable, Kou only pretends to doze off—which is when Nazuna suddenly bites his neck, revealing herself to be a vampire! While Kou thinks the bite will turn him into a vampire, the specifics of transforming are not that simple. In order to change, he must be bitten by someone he truly loves. Ready to let go of his dreary mortal life, Kou decides on a new goal: he will fall in love with Nazuna and become a vampire himself.

Miyo Sasaki is an energetic high school girl who comes from a broken family consisting of her unconfident father and an overly invested stepmother, whose attempts at connecting with Miyo come across as bothersome. Seeing Kento Hinode as a refuge from all her personal issues, she cannot help herself from forcing her unorthodox demonstrations of love onto her crush. While Miyo is unable to get Kento's attention as herself, she manages to succeed by interacting with him in the form of a white cat, affectionately nicknamed "Tarou" by Kento. But Miyo soon realizes that she cannot help Kento with the various problems she overhears in her cat form and is now caught between two tough choices. Will she continue her relationship with him as a cat, or will she reveal her identity and risk what they have in order to help him as her human self?

Emma has been a maid for most of her life. Working for a retired governess—the strict but compassionate Kelly Stownar—Emma has grown to love her work and has long since accepted her place in society. Beautiful, hardworking, and exceptionally kind, Emma has captured the hearts of many of London's working men—but their feelings always remain unrequited. Emma is waiting for love, and she finds it in the most unlikely of places. William is the eldest son of the wealthy Jones household—a family that has only recently been accepted into the gentry, securing their position in high society. He is also the former ward of Mrs. Stownar, and on his first visit in years, he falls madly in love with her maid. His earnest attempts to win her affection, coupled with his good nature and warm personality, have captured Emma's heart. But the polite society of 19th century England does not take kindly to the rejection of tradition. As a result, Emma and William's relationship could not face more opposition. In a world where the class lines are as strongly defended as the borders of nations, does their love have the strength to survive?

Hidden in the backstreets of the Ginza district is Eden Hall, a lone bar operated by Ryuu Sasakura, the prodigy bartender who is said to mix the most incredible cocktails anyone has ever tasted. However, not just anyone can find Eden Hall; rather, it is Eden Hall that must find those who need it. Customers of varying backgrounds, each plagued with their own troubles, wander into this bar. Nevertheless, Ryuu always knows the ideal cocktail to console and guide each distraught soul.