The Ascendancy Paradox

Updated 11/10/2022: The Manuscript has been run through and all known incomplete sentences have been taken care of. A promise and a threat from their kidnappers, "complete their Crucible or face the annihilation of Earth." This is the situation 24 young men find themselves in upon waking up in a barren room. What is the Crucible and what awaits them inside it? Who is behind it? And why were they specifically chosen out of the 7 billion people Earth has to offer?