Morag is 86. She lives alone at the end of a track looking out to sea on her croft on the Isle of Harris, Outer Hebrides, with her three cats and twelve sheep. Morag was born in this house and has lived here her whole life, following five generations of the family who came before her. Cailleach is a portrait of Morag and her simple and peaceful life as she contemplates her next chapter, shares her unique sense of independence and the connection she has to her wild island home.