Fishing fanatic Will Millard heads to the beautiful valleys of West Wales in pursuit of an iconic Welsh fish, the sewin. The region’s rivers are revered by anglers from all over the world, but it will take every ounce of Will’s experience and ability to catch one of their precious fish. He begins his mission at the remote Teifi Pools in the Cambrian Mountains. Here he hopes that a lesson with a local fly-fishing champion will provide the casting skills he’ll need to succeed in the fast flowing rivers in the valley below. But it is not going to be easy. Sewin are wild fish, traditionally caught during the night. Furthermore, it has been one of the hottest summers on record and fish numbers are critically low. Thankfully, a guide who works on a prolific stretch of the River Tywi at Llandeilo has offered to help Will navigate the water in the darkness. Understanding how important fishing is to the heritage of the region will help Will to appreciate the nature of his challenge. He meets an 81-year-old trout fishing legend from Pembrokeshire to learn about the ancient art of fly-tying and hears how the rivers have changed during her lifetime. Before his final attempt at catching a sewin, Will visits a local fishing club in Llandysul for some inspiration. They have been educating the next generation of anglers on the importance of looking after our rivers and the creatures that rely on them.