"Haitai Nanafa" is a slice-of-life anime set in the tropical setting of Okinawa, Japan. The story revolves around Nanafa Kyan, a cheerful and slightly lazy high school girl who lives with her family in a small, traditional Ryukyuan house. Her family runs a local shrine, and their daily lives are intertwined with the spiritual and cultural elements of Okinawan traditions. Nanafa's life takes a turn when she encounters three spirits—Raana, Iina, and Rii—who reside in a banyan tree near her home. These spirits, each with distinct personalities, bring a mix of chaos and charm to Nanafa's otherwise ordinary life.

Raana, a mischievous and energetic spirit, often causes trouble with her antics, while Iina, a more reserved and mature spirit, tries to maintain balance. Rii, the youngest and most innocent of the trio, adds a touch of whimsy to their interactions. The spirits' presence introduces Nanafa and her family to a world where the mundane and the supernatural coexist, blending humor and lighthearted moments with cultural insights.

Nanafa's family plays a significant role in the narrative. Her older sister, Nao, is a diligent and responsible shrine maiden who often clashes with Nanafa's carefree attitude. Their grandmother, Nami, is a wise and nurturing figure who guides the family and helps them navigate the challenges brought by the spirits. The series also features Nanafa's classmates and friends, who contribute to the everyday adventures and comedic situations.

The plot unfolds through episodic storytelling, with each episode focusing on small, self-contained events that highlight the characters' relationships and the unique Okinawan setting. Themes of family, tradition, and the coexistence of the natural and supernatural worlds are central to the narrative. The series balances humor, cultural exploration, and light drama, creating a warm and engaging portrayal of life in Okinawa.