A soundscape for Episode 8. Theia’s half-remembered memory of her daughter humming by the sea's edge, used by Guggy for the brain transfer. Wind howls, thunder cracks, gulls call overhead. Headphones are best. With sound design by Graham Wild and Becky Ripley. Don’t forget to take part in our Forest 404 Experiment to see how you respond to natural sounds at: bbc.co.uk/forest #Forest404