On board of an old well-restored English boat, and pushed ahead by the mistral wind, we sail in and around the Sulcis archipelago in Sardinia. Between the islands of Sant'Antioco and San Pietro, expert marine biologists dive with us down to sea-grass fields to reveal to us the mystery of the Pinna nobilis or Noble Pen Shell and its' magic thread.: sea-silk. A marine biologist and the only international expert of sea-silk, Chiara Vigo uncover its secrets for us. Chiara Vigo with her special personality and philosophy of life, who has transformed the processing of sea-silk into a real art. A thread that, thanks to her, becomes gold and also prayer. A treasure to protect and preserve for future generations. A thread that cannot be sold or undersold, but that needs to be protected so as not to disappear into the depths.