Ryūshi Shiina, an aspiring picture book artist, moves into the boarding house Narutakisō in preparation for his studies at an art school in Tokyo. The boarding house is managed by Kozue Aoba, a cheerful and kind-hearted young woman who harbors multiple distinct personalities, each with unique traits and behaviors. These personalities emerge depending on her emotional state, ranging from a mature and responsible version of herself to a childlike, energetic alter ego. Despite her condition, Kozue is well-loved by the residents of Narutakisō, who adapt to her shifting personas with patience and affection.

The residents of Narutakisō include a colorful cast of characters: Tamami Chanohata, a mischievous and energetic girl who often teases Ryūshi; Megumi Momono, a reserved and studious high school student; Asami Hayasaka, a quirky and eccentric woman with a penchant for inventing strange gadgets; and Sayoko Kurosaki, a mysterious and aloof woman who rarely interacts with others. Each character brings their own quirks and dynamics to the household, creating a lively and often comedic atmosphere.

As Ryūshi settles into his new life, he becomes increasingly drawn to Kozue and her multifaceted nature. His interactions with her and the other residents lead to moments of humor, warmth, and occasional drama. The series explores themes of friendship, acceptance, and personal growth, as Ryūshi navigates his relationships and pursues his artistic ambitions. The episodic structure of the story balances lighthearted comedy with heartfelt moments, gradually revealing the backstories and motivations of the characters.

The narrative maintains a slice-of-life tone, focusing on the everyday experiences and interactions within Narutakisō. While there is no overarching plot, the series builds emotional depth through its exploration of Kozue’s condition and the bonds formed between the characters. The story concludes on a hopeful note, emphasizing the importance of understanding and supporting one another, even in the face of life’s challenges.