Edith Bowman and Colin Murray explore the Stranraer Oyster Festival, sailing into Loch Ryan to Scotland's largest wild oyster bed to discover why they're so special. Baker Briony-May Williams reveals the effort behind every bag of frozen peas, and farmer Meinir Howells goes underground to find the secret of cheesemaking in Harlech. Ryan Hand is in Armagh on the hunt for a healthy ready meal.