"Rainy Cocoa" is a short-form anime series centered around the daily lives and interactions of the staff and patrons of a cozy café in Tokyo. The narrative primarily unfolds within the confines of the café, which serves as a gathering place for a diverse group of characters. The café, named Rainy Cocoa, is run by Aoi Tokura, a young man who manages the establishment with a calm and welcoming demeanor. His brother, Keiichi Tokura, occasionally assists him, adding a familial dynamic to the workplace.

The series introduces a variety of characters who frequent the café, each bringing their own unique personalities and stories. Among them is Shion, a cheerful and energetic barista who often lightens the mood with his playful antics. Another regular is Nozomu, a reserved and thoughtful individual who contrasts with Shion's exuberance. The interactions between these characters, along with other staff members and customers, form the core of the series, highlighting themes of friendship, camaraderie, and the simple joys of everyday life.

Episodes are brief and slice-of-life in nature, focusing on lighthearted moments and small, meaningful exchanges rather than a continuous, overarching plot. The café setting provides a warm and inviting backdrop for these interactions, emphasizing the sense of community and connection among the characters. The series captures the charm of mundane yet heartfelt experiences, offering a gentle and relaxing viewing experience.

As the story progresses, occasional glimpses into the characters' personal lives and backgrounds are revealed, adding depth to their relationships and motivations. However, the primary focus remains on the pleasant and often humorous interactions within the café, making "Rainy Cocoa" a comforting and easy-to-watch series that celebrates the beauty of ordinary moments.