"Tokimeki Midnight" is a manga series that blends romance, comedy, and supernatural elements. The narrative centers around Yako Katsuragi, a high school student who leads a double life. By day, she is an ordinary girl attending school, but by night, she transforms into a mysterious and alluring figure known as "Midnight." This transformation is tied to a curse placed upon her family, which causes her to take on this alternate persona after dark. The curse also grants her supernatural abilities, including enhanced physical prowess and the power to manipulate shadows.

The story explores Yako's struggles to balance her dual identities while navigating the complexities of teenage life. Her nighttime activities often lead to encounters with various supernatural entities and dangerous situations, which she must confront using her newfound abilities. Along the way, she forms relationships with several key characters, including her classmate and love interest, Shun Tokisaki. Shun is initially unaware of Yako's secret but becomes increasingly involved in her supernatural world as the story progresses. Their relationship evolves amidst the chaos of Yako's cursed existence, adding a layer of romantic tension to the narrative.

Other significant characters include Yako's close friends, who provide emotional support and comic relief, as well as antagonists who seek to exploit or destroy her due to her unique powers. The series delves into themes of identity, love, and the struggle to reconcile conflicting aspects of one's life. The plot is driven by Yako's efforts to break the curse while protecting those she cares about, leading to a mix of action-packed sequences, heartfelt moments, and lighthearted humor. The supernatural elements are seamlessly integrated into the high school setting, creating a dynamic and engaging storyline.