C. S. Lewis's book tells us about one of the "excursions" that take place from Hell to Heaven every now and then. Those souls who wish to participate take part in these trips. The space bus comes to pick them up and takes them to the outskirts of Heaven. The purpose is to see the place, and if they like it and want, they can stay and continue deeper into it.

Of course, they will need to undergo a small "operation" to remove any passions that make their lives Hell. (As well as whatever they believe to be their virtue.) They are free to avoid the "operation" and return back. The tragic thing is that most souls prefer to return to Hell.

The more receptive ones want to carry a bit of their Hell into Heaven. They do not intend to detach Hell from themselves. They remain trapped in the passions they nurtured in this life. Even though their old passions are completely dehydrated - utterly dreamlike - they are their "content." They are afraid to sacrifice them... However, it is not possible to marry Hell with Heaven. Hence the title of the book: "The Great Divorce."