The Immortal Abyss (The Threshold Duology Series #2) Katherine Briggs September 2, 2024 Suspense Sci-Fi/Fantasy Young Adult/Teen Christian Fiction New Book Release: The Immortal Abyss—The Threshold Duology Series #2 by Katherine Briggs
The Eternity Gate (The Threshold Duology Series #1) Katherine Briggs September 12, 2023 Sci-Fi/Fantasy Young Adult/Teen Christian Fiction New Book Release: The Eternity Gate—The Threshold Duology Series #1 by Katherine Briggs
