A story of two young people growing up in Scotland. The Scottish dialect is difficult to get through sometimes, and I honestly had no idea what was being said in a couple places, but for the most part, it was easy to follow. George Macdonald has a good way of teaching through story.
The way I see it, Heather and Snow represent joy and adversity in life. Both used by God to make us the people He desires. The most dynamic character is Francis, the son of a rich officer in the army. He loves Kirsty, the daughter of his father's friend and one of his tenants. This love begins as self-love, as he thinks he is being gracious in loving her. Though she doesn't consent to him (and is somewhat repulsed), she is able to influence him for the better because of this love. She has the true love--that which seeks the best for her neighbor. She shows him how to be a man--doing something because it is right and not just because she wants him to. He finds his inadequacy, and turns to the only One that can wake love and give strength to us. It is a good illustration of how God works through people to help (love) those they are closest to, and the waste (hatred) it is not to help those around us. Francis is changed in the heather--the symbol of how love and joy can work to change us.
The snow is a symbol of adversity. God uses it the test the trust of his people. In searching for his children in a snowstorm, David Barclay has a revelation:
Then came the reflection, how little at any time could a father do for the wellbeing of his children! The fact of their being children implied their need of an all-powerful father: must there not then be such a father? Therewith the truth dawned upon him, that first of truths, which all his church-going and Bible-reading had hitherto failed to disclose, that, for life to be a good thing and worth living, a man must be the child of a perfect father, and know him. In his terrible perturbation about his children, he lifted up his heart—not to the Governor of the world; not to the God of Abraham or Moses; not in the least to the God of the Kirk; least of all to the God of the Shorter Catechism; but to the faithful creator and Father of David Barclay. The aching soul which none but a perfect father could have created capable of deploring its own fatherly imperfection, cried out to the father of fathers on behalf of his children, and as he cried, a peace came stealing over him such as he had never before felt.
God also uses adversity as our guide. Bringing us where he wants us, as Kirsty realizes in the storm as she finds a place to rest.
Through joy and adversity God makes us the people he wants us to be.