An alternate universe in which antimatter dominates over positive matter, time runs in reverse, and black stars burn in the stark white depths of space (also referred to as the "negative universe"). On stardate 6770.3 (2270), the dead star Beta Niobe in the positive-matter universe and its counterpart in the antimatter universe, a newborn star called Amphion, formed a temporary gateway between the two universes, through which the U.S.S. Enterprise passed while attempting to prevent a small scout vessel piloted by Karla Five from being destroyed within the Beta Niobe remnant.

The antimatter universe containing the planet Arret may be the same antimatter universe from which the antimatter Lazarus — encountered along with his positive-matter doppelganger by the Enterprise crew on an uncharted planet on stardate 3088.3 (2267) — originated.