New audio restorationist Lin Wan joins Echo Restoration Studio. She refuses blindly pursuing the noise reduction logic of perfection. She firmly believes some noise is time imprints carrying the past. She takes on restoring the only surviving damp old cassette of Pingtan artist Qin Yuehua. During the project, she encounters multiple dilemmas such as AI technology impact, capital price suppression, and traffic coercion. Lin Wan unites with technical rival Cheng Shu, partner Zhou Yan, friend Su He and others, upholding audio authenticity and refusing over-packaging. Choosing with difficulty between efficiency and reality, after three months of refinement, she successfully awakens the live sound sealed for forty years. She also breaks free from a pleasing mindset to complete self-growth.