A metallicity floor near 10⁻⁴ to 10⁻³ solar holds everywhere, in dwarfs, high-z absorbers, and the oldest halo stars, and truly metal-free Population III stars have never been found (Kunth and Ostlin 2000; Wise 2012). Enrichment by scattered first supernovae should be patchy, leaving pristine pockets; the floor's universality is the problem, and simulations impose it by hand.
Star formation in the model begins in sparse, isolated minihalos, so first-generation enrichment is necessarily local and slow to spread. Universal coverage requires Population III yields, mixing, and timing assumptions tuned beyond current knowledge, while the metal-free stars the bottleneck epoch should strand in pristine pockets keep failing to appear.
SCT keeps the chemistry honest at both ends. The cascade thermalized everything above the QCD scale, erasing any prior nuclear history, so BBN proceeds standard (P40, P42) and the universe genuinely starts metal-free; no metals are smuggled in from previous cycles, and the floor must be made in-cycle. What changes is where and when the making happens: collision-seeded proto-structures hold dense gas reservoirs from the deposition epoch, distributed along the cascade-built web rather than in scattered minihalos (P22, P25, P34), so the first stellar generation ignites early, vigorously, and nearly simultaneously across the structure-bearing volume. Its supernovae enrich gas that is already concentrated where all future star formation will occur, which is why the floor is universal: the pristine pockets ΛCDM strands simply never host stars, because star formation and enrichment share the same deposited geography.
This is the same accelerated early stellar history that carries the JADES-GS-z14-0 oxygen abundance and the super-solar nitrogen systems at z above 14 (recid 113): multiple stellar generations fit before the epochs ΛCDM reaches first light, so by the time any surviving observable population forms, the floor is laid. The metal-free Population III stars are not hiding; their generation completed and enriched itself out of existence before the populations we can still observe were born. The seeding mechanics are in Paper 4, From Chaos To Collisothermal Cosmogenesis, with the cascade-termination chemistry in Paper 1, From Chaos to Convergent Foundations.
Keystone economy: P25 places the fuel, P40 and P42 keep the starting composition honest, and the floor follows from geography plus speed.
The kill is the long-sought object itself: a confirmed truly metal-free star, below roughly 10⁻⁶ solar at high significance, would demonstrate a surviving pristine star-forming pocket and refute the universal early-enrichment geography. The timing half is separately exposed: if JWST finds genuinely zero-metallicity star-forming gas at redshifts where SCT's accelerated first generation should already have enriched the web, the fast-and-everywhere reading fails even without a surviving star.