"Listeners" is set in a dystopian world where humanity no longer remembers the concept of music. The story unfolds in a landscape dominated by mechanical creatures known as Earless, which threaten the remnants of human civilization. The protagonist, Echo Rec, is a young boy living in the industrial city of Liverchester. He dreams of becoming a Player, a rare individual capable of wielding a mysterious device called a "Player Unit" to combat the Earless. Players are revered as heroes, but their origins and the true nature of their powers remain shrouded in mystery.

Echo's life takes a dramatic turn when he encounters a mysterious girl named μ (Mu), who is found buried in a junkyard with no memory of her past. Mu possesses a Player Unit embedded in her body, making her a potential Player. Together, Echo and Mu embark on a journey across the world to uncover the truth behind the Earless, the lost history of music, and Mu's forgotten identity. Their quest leads them to encounter other Players, each with their own motivations and connections to the enigmatic forces shaping their world.

As the story progresses, Echo and Mu learn that the Earless are not merely mindless machines but are linked to the forgotten legacy of music. The narrative explores themes of identity, memory, and the transformative power of music, weaving together a tale that blends action, mystery, and emotional depth. The relationship between Echo and Mu evolves as they confront challenges, uncover secrets, and grapple with the consequences of their discoveries. The series culminates in a climactic revelation about the origins of the Earless and the role of Players in restoring the lost harmony of the world.

The main characters, Echo and Mu, are central to the narrative, with Echo representing youthful determination and Mu embodying the enigmatic connection to the past. Supporting characters, such as other Players and figures from Echo's life, add layers to the story, providing context and conflict. The series balances its dystopian setting with moments of hope and introspection, creating a narrative that is both engaging and thought-provoking.