Chapters 3 through 12 of the light novel introduce Phil, a young, exceptionally strong, and somewhat naive individual living in the mountains with her grandfather, Zandolf, a renowned Great Sage. Phil's primary motivation is to gather a Wyvern's liver to cure her grandfather's illness. She possesses immense physical strength and a natural talent for offensive magic, particularly fire, but struggles with delicate magic like levitation. Her grandfather, recognizing her potential, has focused her education on magic, neglecting common sense and social graces.
Phil's initial attempts to hunt a Wyvern are hampered by her inability to use levitation effectively and her grandfather's prohibition on using a forbidden "Flight" magic due to its uncontrollable power. Despite this, she uses the forbidden magic, launching herself into the sky and inadvertently finding herself above a Wyvern. She defeats it with a single, incredibly fast punch, prioritizing the retrieval of its liver for her grandfather.
Upon returning to her grandfather, Phil learns he is gravely ill and believes he is nearing death. He expresses concern about leaving her alone and lacking common sense, resolving to become an immortal king to stay with her, though he acknowledges he may disappear for a time. Phil, however, struggles to grasp the concept of his impending death, believing their peaceful life of studying magic and stargazing will continue forever.
A strange scent leads Phil to investigate a mountain path, where she encounters two travelers: Roen, a knight, and Celica, a noblewoman from the Kingdom of Celestia. They are attacked by a Wyvern, which Phil's grandfather had warned her about as a "small dragon." Roen and Celica easily defeat the Wyvern, revealing their combat prowess. However, a much larger and more powerful Sky Dragon then appears. Phil intervenes with an incredibly potent, un-chanted fire magic, forcing the dragon to retreat, though it is clearly enraged.
Roen introduces himself as a Knight of the Round Table, and Celica reveals herself as a daughter of a Marquis from the royal family, searching for a child of royal blood. Phil, still believing herself to be a boy and lacking social understanding, unintentionally offends Celica by physically examining her chest to confirm her gender, a method taught by her grandfather. Despite this, Celica recognizes Phil's extraordinary power and potential, suspecting she might be the person they are looking for.
Phil guides them to her grandfather's humble, dilapidated home. Zandolf, though frail, greets them and reveals his impending death. He entrusts Phil's care and education to Celica and Roen, requesting they teach her common sense and prepare her for enrollment in the Royal Academy in the capital city. Zandolf then departs, becoming a spirit to watch over Phil.
Celica begins Phil's transformation into a lady, bathing her, styling her hair, and dressing her in a dress, which Phil finds cumbersome. Phil's immense strength and lack of social graces are evident throughout their journey down the mountain. They are attacked by a Roc, a giant bird, which Phil easily repels by summoning a powerful spirit king. They then camp for the night, where Phil is impressed by Celica's cooking and expresses a strong desire to visit the capital city. Phil also experiences unfamiliar feelings when sleeping next to Celica, hinting at a developing emotional awareness. The chapters conclude with Phil's departure from her mountain home, embarking on a new journey to the capital with Celica and Roen.
