Chapter 12 It is to be known that on the night of the Feast of Samhain the doors separating this world and the next one are opened, and the inhabitants of either world can leave their respective spheres and appear in the world of the other beings. Now there was a grandson to the Dagda Mor, the Lord of the Underworld, and he was named Aillen mac Midna, out of Shi' Finnachy, and this Aillen bore an implacable enmity to Tara and the Ard-Ri'. As well as being monarch of Ireland her High King was chief of the people learned in magic, and it is possible that at some time Conn had adventured into Tir na n-Og, the Land of the Young, and had done some deed or misdeed in Aillen's lordship or in his family. It must have been an ill deed in truth, for it was in a very rage of revenge tha