Joe Mahon visits the shores of Lough Swilly in County Donegal. He is shown around Fort Dunree by John McCarter who explains its strategic military importance during the Napoleonic Wars and Word War I, having been set up following the 1798 Rebellion. He tours the large guns, which boast that they have never been fired in anger, and the remains of the abandoned soldiers' living quarters.

Sister Eveleen Hallahan of the Loreto nuns shows Joe around the house of the one time local landowner which the sisterhood bought for £250 in 1928 for use as a summer home. She then shows Joe a labyrinth in the grounds of the house and explains the religious and spiritual background of labyrinths from the Middle Ages.

Joe looks at a monument to Wolfe Tone and the United Irishmen Rebellion and another to John Doherty, the 19th Century socialist reformer who was born nearby. Dessie McCallion shows Joe around the remains of farm dwellings in the hillsides explaining how the tenants would have lived.

Alan Rooks shows Joe around the interior of Castle Linsford, the local 'big house', which he now runs as a bed and breakfast. Brigeen Clafferty then shows Joe around the gardens and her examples of topiary. Joe then returns to Dunree in the evening to help illuminate the old searchlight using old technology involving carbon rods. We cut first to local conservationist, Emmett Johnson, who shows Joe a collection of porpoise and whale bones from the area. Back at the searchlight the mechanism is working and picks out the local lifeboat in the dark. The following day Joe goes on a training exercise with the lifeboat's skipper, Mark Barnett.

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.