Tir Nan Og is the legendary Celtic Land of the Young, a world rather like a legendary version of Northern Europe in a time before much of that continent sank beneath the waves. The four Tribes of the Earth Goddess, on whom the Sláine stories concentrate, are threatened on all sides, with the constant risk of the Fomorians sweeping down from the icy north, the Drune Lords encroaching from the south and the ravages of the berserkers of Midgard in the east. Tir Nan Og is a land full of heroes, and full of great quests for those heroes to do. This supplement aims to provide all you need to know to wander the Land of the Young for decades, whether as a mercenary or cattle-rustler, thief or adventurer, tribal emissary or war-band leader. All the major regions of Tir Nan Og are covered, particularly places of interest and general geography. The Sessair: The tribe that stands up. These people consider themselves the strongest, the fiercest and most valiant of the four tribes. The Finians: The tribe that endures. Both proud and stubborn, Finians do not budge when their beliefs and customs are attacked. The Fir Domain: The tribe of the growling shields. The Fir Domain have a reputation for civility and sophistication. Their wisdom is not only found in their counsel. The Fir Domain fight using that most unlikely of Celtic weapons - a plan. The Falians: The tribe of the shadows. Few things can unite the Sessair, Finians and Fir Domain in a unanimous opinion, but the Tribe of the Shadows, or Falians, is definitely one of them. Dinas Emrys and the Cambrian Mountains: Dinas Emrys is known as the Eternal Fortress, because it has always been atop Snowdon and always will be. The Gaesatae: Information on the gaesatae, the bands of Goddess-worshipping elite mercenaries who wander Tir Nan Og. Lands of the Drune Lords: Detailing the lands of the enemy, the sourlands and forbidding country of the Drune Lords where they plot to bring about Ragnarok. The Borderlands: The lands that lie between the Tuatha de Danann and the Drunes are predominantly occupied by two of the world's oldest civilisations, the Titans and the Fir Bolg. Midgard: Wedged between icy seas, towering mountains and the domains of the earth goddess tribes sits Midgard, the land of the Norse tribes that are the children of Voden. Scenario Hooks: Scenario hooks and ideas to be used as is, or adapted to your own campaign to help bring the Land of the Young to life. Encounters in Tir Nan Og: Random encounters particular to Tir Nan Og, certain to liven up any long journey.