Catherine, a native of Riven, had been chosen by Atrus as his bride, and that she was transforming into a god who would one day rule Riven forever. From this series of revelations was born the Moiety, dissidents in rebellion against the oppressive and tyrannical rule of Gehn.

The Moiety survived at first in a vast system of interlinking caves beneath the surface of Riven. Eventually, and with Catherine's help when she returned to her native world, the Moiety was able to secure a burned book from Gehn's labratory, and with this Catherine was able to write the rebels and age of their own, a safe refuge from the tyrant's predations. They adopted a kind of stylized dagger as their emblem; their introduction of these daggers, manufactured in the Moiety Age, puzzled Gehn when he realized that the materials could not be coming from Riven. Catherine, to her dismay, was nothing less than a savior figure, a goddess in her own right come to deliver her people.

The Moiety Age, accessed through secret caverns and by cunningly contrived puzzles, might one day prove to be salvation of the Rivenese. Unfortunately, before she could carry her plans further, Catherine was captured by Gehn and imprisoned on a tiny island, a fragment of the much larger, original isle of Riven.

Gehn's meddlings were taking their

toll, and Riven was disintegrating faster and ever faster. Worse, perhaps, Gehn's tinkerings had also changed the infrastructure of Riven to the extent that he could introduce certain key ingredients for his use. For example, a particular species of beetle that provided the necessary dyes for ink, a special type of tree whose pulped wood made paper of the proper fineness, tooth, and texture. He'd written all he needed into Riven; it seemed to enable him to continue his research into creating his own linking books. It took him thirty years, but eventually he did it. After hundreds of trials, after hundreds of failures, Gehn succeeded in creating a new world—his 233rd age—a haven from which he could complete his experiments.

Soon he would be free of crumbling Riven forever.

Atrus, meanwhile, was beset with the problem of what to do about Gehn. Fearing that Catherine was lost on Riven, he could not simply return to that age with a linking book, not if that meant that Gehn might seize the book and use it to effect his own escape. He feared, too, the immenent breakup of Riven, which was accelerating. His efforts were dangerously delayed by the rebellion of his sons, Achenar and Sirrus, in the Myst affair. Carried away by megalomania and greed (had they been touched by the disease of Atrus' father as well?), they trapped Atrus in D'ni, leaving him helpless, save for the writings with which he could implement certain changes in dying Riven.

Working furiously for many months, he managed to write those changes into Riven's matrix, slowing the destruction, but he knew with cold certainty that the final Armageddon of