Following the nuclear fallout of an event known as The Collapse, survivors in the Welsh hamlet of Tragumna have managed to rebuild peaceful lives for themselves through community, caring for crops and livestock, and living off the land.

This tranquility, however, is jeopardized by the looming threats of plague and invasion. Thus, Tegwynn Galander must travel to the island now known as Faïl to meet its leaders and request that Tragumna's people be allowed to resettle there. On Faïl also grows a special medicinal plant-one needed to treat the chronic radiation burns of Teg's friend, Vanessa, whose condition constantly risks worsening.

But Faïl will be more than just a difficult journey through the wilderness. Strange individuals- some benevolent, some dangerous-await Teg on his journey, as do romance, an awakening to esoteric spirituality, and encounters with beings straight from Celtic folklore. In the end, Teg's quest may force him to brave horizons even further than Faïl, ones of which he had never previously even dreamed.