Leo, a solitary audio technician, accidentally records a pure harmonic tone (labeled "Aaa") during a thunderstorm. When played back, the tone freezes every clock, every heartbeat, every atom in motion — except Leo's. At first, he explores a silent, paused world. But he soon finds others who have also escaped time’s grip: a physicist, a child, and a mysterious figure who wants to erase time permanently. Leo must decide whether to restore the flow of existence or trap everyone in an eternal, frozen present.