"Healer Girl" is a 12-episode anime series set in a world where medical treatment is enhanced through the use of vocal therapy, known as "medical song therapy." The story centers on three young apprentices training to become professional medical song therapists under the guidance of their mentor, Dr. Shibata. The main characters include Kana Fujii, a passionate and determined girl with a natural talent for singing; Reimi Kisaragi, a disciplined and methodical student with a strong sense of responsibility; and Hibiki Morishima, a cheerful and energetic individual who brings a lively dynamic to the group.

The narrative explores their journey as they learn to harness the power of song to heal physical and emotional ailments. Each episode delves into their training, personal growth, and the challenges they face in mastering the art of medical song therapy. The series balances lighthearted moments with more serious themes, as the characters encounter patients with varying conditions, from physical injuries to psychological trauma. Through these experiences, the apprentices develop their skills and deepen their understanding of the connection between music, emotion, and healing.

The setting is a near-future world where medical song therapy is an established practice, blending traditional medical techniques with the therapeutic power of music. The series emphasizes the importance of empathy, teamwork, and perseverance, as the characters work together to overcome obstacles and improve their abilities. While the focus is primarily on the apprentices, Dr. Shibata plays a crucial role as their mentor, providing guidance and support while challenging them to grow.

The plot progresses through episodic patient cases, each highlighting different aspects of medical song therapy and the personal struggles of the characters. As the series unfolds, the apprentices face increasingly complex situations that test their resolve and push them to refine their craft. The narrative culminates in a final arc where the characters must confront their own limitations and work together to achieve a significant breakthrough in their field. The series concludes with a sense of accomplishment and growth, leaving the characters poised to continue their journey as skilled medical song therapists.