"D4DJ Double Mix" is a two-episode anime series that serves as a spin-off of the "D4DJ" multimedia franchise, focusing on the interactions and dynamics between characters from different units within the franchise. The narrative centers on Rinku Aimoto and Maho Akashi from Happy Around!, who find themselves collaborating with Muni Ohnaruto and Rei Togetsu from Peaky P-key. The story begins with Rinku and Maho encountering Muni and Rei during a casual outing, leading to an impromptu musical collaboration. The characters bond over their shared passion for DJing and music, exploring themes of creativity, teamwork, and the joy of performance.

The plot unfolds as the four characters decide to create a unique DJ set together, blending their individual styles and strengths. This collaboration highlights their contrasting personalities: Rinku's cheerful and spontaneous nature, Maho's confident and driven attitude, Muni's reserved yet determined demeanor, and Rei's calm and supportive presence. The series emphasizes their growth as they navigate challenges, such as creative differences and technical hurdles, while preparing for their performance. The narrative is driven by their interactions, showcasing how their diverse perspectives and skills complement each other.

The series also incorporates elements of the franchise's broader lore, such as the importance of live performances and the vibrant DJ culture that unites the characters. While the story is lighthearted and focused on character dynamics, it provides insight into the collaborative spirit that defines the "D4DJ" universe. The two-episode format allows for a concise yet engaging exploration of the characters' relationships and their shared passion for music, making it an accessible entry point for both new viewers and existing fans of the franchise.