Scotland: Ocean Nation

We join Cal on her paddleboard as she sets off from Glasgow city centre, following the River Clyde out to sea. Ahead of her lie vast ocean crossings as she island-hops past whirlpools to Arran, Mull to Skye. We get our first glimpse into Scotland's surprising underwater world, to experience what is often out of sight and out of mind, and hear about some powerful community projects to protect it.