We follow mad Sweeney in his crazed wanderings through the forest and hills, torn within himself by his love of the wild and his incurable loneliness. The tale is presented as chunks of narrative interspersed with segments of poetry, their quiet, melancholy beauty evoking the sounds of windsong and rain.

There is an ethereal quality to this text that makes it difficult to describe. Although it would seem to have a storyline, in reality it is a song, and each "event" a new strain of music. Sweeney's longing for his lost life as a man and king, even as he is unable to stay away from his beloved wilds of Glen Bolcain, illustrate the conflict between the desire for peaceful conformity and for transcendence. This conflict is echoed in the struggle that was ensuing in Ireland even as this work was being written, the struggle between the Celtic religion and the new influx of Christianity.

In this way does "Sweeney Astray" illuminate a historic revolution, while at the same time presenting themes that span eternity.