Tir-nan-óg: Descendants of Danaan is a role-playing game based on Irish mythology, more specifically the story of Tír na nÓg (the land of eternal youth) and the Tuatha Dé Danann (people of the goddess Dana). The main plot of the game is only loosely based on actual Irish myths and involves the fictional kingdom of Annafofo, the assault of demons, the abduction of the princess, and a legendary hero who must rectify all that and restore peace in the land.