The Parallax Threshold. The Parallax Cosmos, #2

When reality splits, survival becomes a matter of which version of the truth you can hold onto. A remote deep-space platform detects an impossible phenomenon: two identical Earths overlapping in the same region of space, separated by a thin, unstable boundary known only as the Parallax Threshold. At first, the discovery promises a breakthrough in understanding the structure of the universe. Then the data begins to contradict itself.
Signals arrive before they are transmitted. Star charts shift without cause. Crew members witness events that never occurred, while others remember outcomes that have yet to happen. The line between observation and participation begins to collapse. As the boundary destabilizes, the truth emerges. This is not a window into another world. It is a convergence. Two realities are being forced into one, and the process is accelerating.
With systems failing and time running out, the crew must navigate a growing cascade of anomalies while trying to understand the forces behind the collision. Every attempt to stabilize the threshold only deepens the instability. Every decision carries consequences across both worlds. Caught between parallel existences and irreversible outcomes, they must determine what can be preserved and what must be lost.
Because when the threshold finally collapses, only one reality will remain.