"Koaruhii Daisuki!" centers on the life of Haruto, a high school student with a deep passion for coffee, who dreams of becoming a skilled barista. The series explores his journey as he navigates the challenges of mastering the art of coffee-making while balancing the demands of school and personal relationships. Haruto's fascination with coffee begins when he stumbles upon a small, family-owned café run by an elderly barista named Sora, who becomes his mentor. Under Sora's guidance, Haruto learns the intricacies of brewing, the importance of precision, and the cultural significance of coffee.

The narrative delves into Haruto's interactions with his classmates, particularly Aoi, a spirited and ambitious girl who shares his enthusiasm for coffee. Together, they form a coffee club at school, where they experiment with different brewing techniques and compete in local barista competitions. The series highlights their growth as they face setbacks, learn from failures, and develop their unique styles. Alongside Haruto and Aoi, the supporting cast includes Riku, a laid-back friend who provides comic relief, and Yuna, a meticulous perfectionist who challenges Haruto to refine his skills.

As the story progresses, Haruto and his friends encounter rival baristas, each with their own philosophies and methods, adding depth to the competitive aspect of the series. The café setting serves as a backdrop for exploring themes of perseverance, friendship, and the pursuit of excellence. Through its focus on the art of coffee-making, "Koaruhii Daisuki!" offers a blend of slice-of-life storytelling and lighthearted competition, appealing to audiences interested in character-driven narratives and niche hobbies.