The idea for the programme is that the poet Ifor ap Glyn goes on a journey around Wales to see how many Welsh speakers he can find, and he does it all in Welsh. It's surprising how even people who claim they don't speak Welsh often know a bit.
I watched episode one while crocheting. Ifor ap Glyn visited Llanover and Abergavenny, both very anglicised areas, but even there he found native speakers, school children who could speak Welsh and adults who were learning the language.