Seeking new inspiration and a fresh start, married musicians Daphne (Rosy McEwan) and Darcy (Dev Patel) move to the Welsh countryside to finish their new record. While collecting audio samples, Darcy inadvertently creates a field recording of mysterious sound never before heard by human ears. The discovery renews Daphne's creative energy, but as the echoes of her music bleed into the surrounding landscape, ancient and malevolent woodland forces are disturbed.