Halcyon Ring Navigation Chart — The Marrow

The eastern maintenance corridor was never supposed to become a rescue route.

By the time the Wren entered the Halcyon field, most current charts were already useless. The ring had been broken for fifteen years, and fifteen years was more than enough time for debris to drift, reactor cores to keep bleeding interference, and old structural sections to settle into new rhythms no survey team had bothered to record.

The pilots who still spoke about the region called it the Marrow. This chart marks the route the Wren took through it twice in one day.

The first passage followed what remained of the old maintenance corridor: past shifted debris, through a ghost-current field strong enough to blind the ship’s instruments, across the cryogenic vent zone, and finally through the Fold — two massive ring sections still opening and closing around a shared broken axis.

The annotations were added after the first crossing.

DO NOT TRUST OLD INTERVALS.

WATCH SHADOW PATTERNS.

VENTS CLEAR ~20 SEC.

INSTRUMENT FAILURE NEAR CORE BLEED.

They were not part of any official survey. They were what Nova Hoshizaki knew. The return passage proved why the distinction mattered. The Fold no longer matched the timing logged on the way in.

The Wren’s own passage had shifted the rhythm enough that the earlier window could not be trusted. Nova waited through another full cycle, recalculated by sight, and took the ship through only when the opening looked right. The chart was updated again afterward. No new safe corridor was declared. No restriction was lifted.

The Halcyon Ring remained exactly what it had been before the rescue: unstable, uncharted in all the ways that mattered, and officially closed to traffic. But for one day, there was a route through the Marrow. And the Wren flew it twice.