This week we meet Lewis' Virgil: George MacDonald. And we discover the core idea of the book, well summarized in this quote:

"Never fear. There are only two kinds of people in the end: those who say to God, 'Thy will be done,' and those to whom God says, in the end, 'Thy will be done.' All that are in Hell, choose it. Without that self-choice there could be no Hell. No soul that seriously and constantly desires joy will ever miss it. Those who seek find. To those who knock it is opened."