The Dark Reading Matter is a theoretical realm that suggests that the observable bookverse can only account for 20 percent of the calculated total readable mass. Out there somewhere, possibly, is a larger and more expansive and unseeable "Dark Bookverse" that contains millions of deleted novels, slush-pile manuscripts, lost poems, forgotten pop culture references, long unheard oral tradition, stories and ideas that were still in people's minds when they died.

The Goliath Corporation hopes to exploit the Dark Reading Matter for profit, and Thursday Next is once again pitted against a familiar foe. A visitor named Roger Thatt who purports to be from Fourth Wall Publishing has some peculiar ideas of his own that require careful thought. Is Thursday and everyone she knows living in a simulation? Was her world created from scratch Last Thursday as Roger supposes, and are the books she reads the only direction in which books can be read?

With existential questions the least of her troubles and a family to take care of, Thursday must defeat the Goliath Corporation, ensure that a tear in the fabric of the Bookworld does not suck all literature from hers, and conclude her own series so she can enjoy a comfortable retirement, while dodging the threat of the worse fate imaginable for a story: The Scooby Doo ending.