Actor Simon Delaney explores the history of Ireland's greatest castles by discovering the stories and characters associated with them. The documentary includes exceptional aerial footage of Ireland, and cameras capture lesser-known areas of the island. Beginning with the 12th century, Delaney discusses the political state of Ireland, when events led to the Norman invasion in 1169. Ireland's landscape changed as well, featuring a unique style of building and towers. Delaney visits some of the earliest Norman castles along the east coast, stopping in Dublin and Carrickfergus before going to Limerick and Mayo.