In today's society, so focused on visual impulses, radio is a unique universe. Director Nicolas Philibert takes us on a journey of discovery at Radio France. This usually invisible world unfolds as surprisingly fascinating. The film focuses on several radio hosts, each typified by their unique style, their charisma and their dry sense of humour. We also meet many radio guests, such as author Umberto Eco and musicians whose live performances give the film an exciting soundtrack.