Dr. Helen Czerski examines the extraordinary messages sound waves carry and how they help us understand the world around us. Visiting a hidden location buried beneath the hills of Scotland, Helen experiences some of the most extreme acoustics in the world. She discovers how sound has driven the evolution of biological systems and complex relationships between creatures that exploit sound. Through the story of a cochlea implant patient, Helen explores the complicated way our ears can translate sound waves. On the North Sea, she investigates how marine archaeologists use sound waves to uncover human stories buried beneath the sea.