"Mori no Ongaku-dan" is a narrative centered around a group of anthropomorphic animals living in a forest, who come together to form a musical band. The story unfolds in a serene woodland setting, where the characters, each representing different species, share a common passion for music. The main characters include a rabbit, a bear, a fox, and a bird, each bringing unique musical talents and personalities to the group. The rabbit is a skilled violinist, the bear plays the drums, the fox is a guitarist, and the bird sings with a melodious voice.

The plot revolves around their journey to create harmonious music that resonates with the natural world around them. As they practice and perform, they encounter various challenges, such as overcoming personal insecurities, resolving conflicts within the group, and dealing with external threats to their forest home. These challenges often serve as metaphors for broader themes like teamwork, perseverance, and the importance of preserving nature.

Throughout the series, the band performs in different parts of the forest, each location offering a unique backdrop that enhances their music. Their performances attract other forest creatures, fostering a sense of community and shared joy. The narrative also delves into the backstories of the main characters, revealing their motivations and the events that led them to join the band. These backstories add depth to their interactions and highlight the diversity of their experiences.

As the series progresses, the band faces a significant threat when their forest is endangered by human activities. This crisis tests their unity and resolve, pushing them to use their music as a means of advocacy and resistance. The climax of the story sees the band organizing a large concert to raise awareness about the plight of their home, culminating in a powerful performance that unites the forest inhabitants and draws attention to the importance of environmental conservation.

The series concludes with the band continuing their musical journey, having grown stronger and more cohesive through their shared experiences. Their story serves as a testament to the transformative power of music and the enduring bonds of friendship and community.