A short story set approximately 14 years after the events of Signal Zero.

The Null Margin was what you got when someone who loved you handed you both their best asset and their worst debt simultaneously, and then had the poor timing to die before you could argue about it.

Fourteen years after my mother first flew her through a Flux-scoured trade corridor on the edge of what most people called the Fringe and most other people called “the reasonable boundary of human habitation,” the ship was still running. Barely, and with the mechanical personality of a grudge, but running. The Integration overlay had been active for about as long. Though my mother had been five years into her relationship with the system when she died, I had been significantly less committal about the whole thing.

The overlay was present. I’d acknowledged that much. It floated in the upper-right quadrant of my vision like an uninvited houseguest who had decided the question of their residency was settled and I was simply going to have to adapt. The numbers there were the same numbers that had been there last month and the month before: Integration Level 7, Designation SCOUT, and a set of attributes I’d learned not to look at too closely on the grounds that looking at them too closely felt like reading your own autopsy.

My mother had found the system meaningful. She’d invested her stat points with intention, studied the designation trees, asked the other Fringe captains about skill drops and Rift schedules. “It’s a tool,” she’d told me, the last time we’d disagreed about it. “You don’t stop using a navigation computer just because you don’t understand how it works.”

She’d been right, probably. But she’d also been running cargo through the Kaspar Corridor when the Unintegrated came through it, and neither the Integration nor any of her carefully allocated attribute points had changed how that ended.

So. Not a tool I was in the habit of picking up.

The problem with the Fringe, as a category of space, was that the Integration’s influence thinned at its edges the way a signal did, functional in the center, increasingly unreliable toward the periphery, and at the actual boundary, capable of delivering readings that were technically data and practically useless. Holdfast Station sat in what system analysts charitably described as a “variable-density Integration zone” and what every ship captain who regularly docked there described using language that wouldn’t survive transcription.

I’d been docked four hours when the Flux Storm rolled in.

Category 2, the overlay said. Then it revised to Category 3 before I’d finished reading the initial alert, which was the sort of immediate recategorization that made a person trust prediction algorithms very little going forward.

The timing was not ideal. An hour earlier I’d taken on a passenger. Brem, a twenty-four-year-old engineer from the Steady Margin (not my ship; different Margin; the name coincidence was either a good sign or a terrible one, and I’d been unable to decide which), whose captain had experienced a medical emergency mid-run and been carried off to Holdfast’s medical bay. Brem had been standing on the dock with the expression of someone whose entire professional situation had just become significantly non-standard, and I’d done the thing I always regretted: offered a berth. He was quiet, which I appreciated. He was competent with tools, which I discovered when he asked if he could do something useful, and I handed him three faults from the Null Margin’s maintenance queue without expecting much, and he cleared all three in forty minutes.

The Flux Storm did not care about any of this.

What a Category 3 Flux Storm did to navigation systems was the same thing it did to most precision instruments: it introduced an uncertainty principle with teeth. My overlay flickered. Brem’s eyes went slightly unfocused in the way that happened when a person’s overlay was throwing static. The Null Margin’s navigation suite, which ran on conventional tech with a system-assisted layer bolted on top, started producing readings that disagreed with themselves in interesting ways.

I looked at the readings. I looked at Brem.

“How are you with pressure suits?” I said.

The Null Margin’s external navigation array was a hybrid unit, and the hybrid nature meant that when the Flux disruption hit the system-assisted layer, it created a feedback loop that was slowly corrupting the conventional layer’s baseline calibration. This was a fixable problem if you went outside and physically reset the calibration node, which was located on the ship’s underside in the spot the designer had clearly chosen by picking the worst possible option from a list.

“You should not do this,” Brem said, with the tone of someone who had assessed the situation and arrived at a professionally responsible conclusion he fully expected to have ignored.

“I know,” I said.

“The external atmosphere is Category 3 Flux-active. Your stats—”

“I know.”

He looked at the overlay in his own visual field, running numbers I couldn’t see. “Your Flux is nine. The storm is already producing localized distortions. For someone with a nine, that’s going to feel like—”