Back Cover: Part Four of the Horned Lord and Moon Sow Campaign
From the introduction (spoilers):
Welcome to Way of the Horned God, the fourth adventure in the Horned Lord and Moon Sow campaign for the Slaine Roleplaying Game. In this epic adventure, the heroes will need to free their tribe from Fomorian tyranny, quest for the tribal treasures of the other three Tuatha de Danaan, unite the four Tribes of the Earth Goddess under a single High King, re-establish the religion of Carnun and assemble the last of the magical Teeth of the Moon Sow to create a
magical artefact of immense power!
This adventure is intended for 8th level characters from the Fir Domain tribe. It best suits a party composed mostly of warriors, with perhaps one druid, witch or thief. An all warrior party can complete the adventure, so long as they have a wide variety of skills. Ideally, the party should have completed the first three adventures in the campaign, The Invulnerable King, The Teeth of the Moon Sow and The Ragnarok Book but notes are included for Player Characters who have not played in those adventures.
All you need to play Way of the Horned God is this book, a copy of The Player’s Handbook and the Slaine Roleplaying Game rulebook. The first Slaine supplement, Tir Nan Og, would be useful for additional background but is not essential; the same is true of the Fir Domain tribe book.