"My Monster Girl's Too Cool for You" centers on the life of a high school student, Kouta, who finds himself entangled in the supernatural when he encounters a mysterious girl named Lilith. Lilith is a monster girl, a being with supernatural abilities and a striking appearance that sets her apart from humans. Despite her intimidating demeanor and otherworldly nature, Lilith begins to develop an unexpected bond with Kouta, who is initially wary but gradually becomes drawn to her unique personality and charm.

The narrative explores their evolving relationship as Kouta navigates the challenges of balancing his ordinary life with the extraordinary circumstances brought on by Lilith's presence. Lilith, while powerful and confident, harbors vulnerabilities and a desire to understand human emotions, which she explores through her interactions with Kouta. Their dynamic is further complicated by the arrival of other monster girls, each with distinct abilities and personalities, who enter Kouta's life and create a blend of comedic, dramatic, and occasionally tense situations.

Themes of acceptance, identity, and the coexistence of humans and supernatural beings are woven into the story. Kouta's journey involves reconciling his feelings for Lilith while dealing with the societal and personal implications of their relationship. The series balances lighthearted moments with deeper emotional undertones, offering a mix of humor, romance, and supernatural intrigue. The characters' growth and the exploration of their relationships form the core of the narrative, making it a compelling blend of slice-of-life and fantasy elements.