Jack was an ordinary California college student, quiet and awkward, into vegetarianism and healthy living, dreaming of quietly finishing school and finding a stable normal job. One day, in the library's underground old book vault, he accidentally opened a pitch-black ancient tome and accidentally summoned the 300-year-dormant vampire ancestor Carmilla. Carmilla claimed the taste of Jack's blood was her fated "true love"—she must make him fall in love with her to break her curse and return to the demon realm (Night Realm). The problem was, Jack had zero interest in this "cross-species pure love" and just wanted a healthy normal life. His goal became: find a way to send Carmilla back. Otherwise, she'd keep pestering him and wrecking his vegetarian lifestyle and life plans. Worse, Carmilla's gothic-aristocrat "seduction" behavior caught the attention of campus arts goddess Olivia and tsundere punk underclassman Scarlett, who both inexplicably developed a strong interest in Jack.