"Sono Ki ni Sasete yo My Mai Mai" centers on Mai Mai, a young girl with a vivid imagination and a penchant for daydreaming. Her life takes an unexpected turn when she encounters a mysterious talking cat named Myao, who grants her the ability to bring her imaginative creations to life. This newfound power allows Mai Mai to transform her whimsical ideas into tangible, often chaotic, realities. However, the ability comes with its own set of challenges, as Mai Mai must navigate the consequences of her creations, which frequently spiral out of control.

The narrative explores Mai Mai's daily life, blending slice-of-life elements with fantastical scenarios. Her interactions with classmates, family, and Myao form the core of the story, highlighting her growth as she learns to balance her imaginative world with the responsibilities of reality. The series delves into themes of creativity, responsibility, and the fine line between fantasy and reality, often using humor and lighthearted moments to underscore its messages.

Mai Mai is portrayed as a spirited and curious protagonist, whose boundless imagination drives much of the plot. Myao, the enigmatic cat, serves as both a guide and a source of mischief, often complicating Mai Mai's efforts to manage her powers. Supporting characters, including Mai Mai's friends and family, provide additional layers to the story, offering contrasting perspectives on her adventures and grounding the fantastical elements in relatable human experiences.

The plot unfolds through episodic chapters, each presenting a new scenario where Mai Mai's imagination runs wild, leading to humorous and sometimes poignant outcomes. The series maintains a balance between comedic escapades and moments of introspection, creating a narrative that is both entertaining and thought-provoking. Through its exploration of Mai Mai's journey, "Sono Ki ni Sasete yo My Mai Mai" offers a unique blend of fantasy and everyday life, capturing the essence of childhood wonder and the challenges of growing up.