"Oshiete Mahō no Pendulum: Rilu Rilu Fairilu" is a magical girl anime series that centers on the adventures of the Fairilu, tiny fairy-like beings who inhabit a whimsical world connected to the human realm. The Fairilu are born from magical seeds and possess unique abilities tied to their individual personalities and traits. Each Fairilu is associated with a specific flower, insect, or other natural element, which influences their powers and roles in their world.

The story primarily follows Lip, a cheerful and curious Fairilu who aspires to become a great fairy. Lip is born from a rose seed and possesses the ability to communicate with flowers. Alongside her are other Fairilu friends, including Sumire, a shy and kind-hearted violet Fairilu; Himawari, a sunny and energetic sunflower Fairilu; and Suiren, a water lily Fairilu who is calm and nurturing. Together, they navigate the challenges of growing up, learning about their powers, and helping others in their magical world.

The narrative explores the Fairilu's interactions with humans, as they occasionally cross into the human realm to assist those in need or to learn more about human emotions and experiences. The Fairilu also face various trials, such as solving problems in their own world, overcoming personal insecurities, and protecting their environment from disturbances. The magical pendulum, a key element in the series, serves as a bridge between the Fairilu world and the human world, enabling the Fairilu to travel between the two realms.

Throughout the series, the Fairilu grow and mature, learning valuable lessons about friendship, responsibility, and the importance of embracing their unique qualities. The story emphasizes themes of cooperation, self-discovery, and the interconnectedness of nature and magic. The episodic structure of the series allows for a variety of standalone adventures while maintaining an overarching focus on the Fairilu's development and their harmonious coexistence with both their magical and human worlds.