Presenter Joe Mahon visits Rathlin Island off the coast of County Antrim. Joe sails across from Ballycastle to Rathlin Island recountig some of the violent history of the island's historical battles. Onshore he meets RSPB warden Liam McFaul, as they gaze upon the flocks of seabirds on the island's cliffs and discuss how the eggs were once a staple part of the islanders' diet.

Joe talks of the history of Rathlin during the Middle Ages and Tudor times and shows the remains of Bruce's Castle. Marine archeologist, Wes Forsythe, shows Joe evidence of ruined kilns for a kelp industry on the shore. This in turn was used in the linen industry and, once iodine was discovered in it, by medicinal and photographic industries.

Joe stands beside a memorial to the famine and tells how Rathlin lost half its population to emigration in its aftermath. Peggy McFaul sits in her garden and tells Joe of her life on the island since the 1940s and of the hardships she remembers growing up there. Her grandson, Benji McFaul, is the last full-time fisherman on the island and talks to Joe from his boat. Julie-Ann McMullan tells Joe of how she left a good job on the mainland to live on the island and shows her collection of animals including donkeys and a Shetland pony.

Lesser Spotted Ulster is a long-running and popular programme that visits the places many of us have heard of but never been to. Presenter Joe Mahon gently explores what makes a place what it is.