What makes a story Catholic or Christian?

Beneath the surface answers (the positive portrayal of faith, the assertion of a moral universe), we find another one:

Hope.

Against a world-weary culture, Christians dare to hope. This hope changes the tenor of a story. Christians still write redemption arcs. (How naïf!) And when Christians write a tragedy, the story is told against the backdrop of God—overtly or subtly, He’s there, whether or not the characters embrace Him.

Matters of content, genre, form, artistry, and audience aside—and we can debate these points until we’re blue in the face—a novel is Catholic or Christian insofar as our crazy, childlike hope in a Redeemer makes its way into the fabric of the story.

Hope.

Wonder.

Credo.

This flies in the face of contemporary fiction and Western culture. Consider these words of Cardinal Sarah:

Saint Thomas Aquinas says that the major remedy for acedia is not in us but in God. It is the Incarnation, the coming of God in our flesh. Indeed, since heaven seems so far away and we can grow tired in our search for God, he himself came to meet us so as to facilitate our desire to love him, so as to make tangible the good that he offers us. In this sense, I think that the feast of Christmas is the moment when it is easiest to fight against acedia. In contemplating the manger and the Infant Jesus, who makes himself so close, our hearts cannot remain indifferent, sad, or disgusted. Our hearts open and warm up. The Christmas carols and the customs that surround this feast are imbued with the simply joy of being saved…

The West sometimes resembles an embittered old man. It lacks the candor of a child. Spiritually, the continents that came to know the Good News more recently are still astonished and enchanted by the beauties of God, the marvels of his action in us. The West is perhaps too accustomed to it. It no longer shivers with joy before the manger scene; it no longer weeps with gratitude before the Cross; it no longer trembles in amazement before the Blessed Sacrament. I think that men need to be astonished in order to adore, to praise, to thank this God who is so good and so great. Wisdom begins with wonder, Socrates said. The inability to wonder is the sign of a civilization that is dying.

— Robert Cardinal Sarah, "Acedia and the Identity Crisis,” The Day is Now Far Spent, pp. 126-7

The world is drowning in acedia. This is why Hallmark Christmas movies are so dang popular—people are trying to recapture the wonder. This is why most literary fiction remains unread, outside of a chosen few—people do not have the stomach for any more darkness. Or, at least, they do not have the stomach for darkness without redemption.