The next morning, Gillian left her small cabin on the West Side half-G level to attend the Captain's emergency meeting. As she walked to the elevator concourse, she was aware of people staring at her with anxiety. Video of Abel's incident had been splashed across the ship's news for days, accompanied by Gillian's face - the only person now available to pilot the ship.

Gillian had grown accustomed to occasional greetings and encouraging words. But the gazes now directed at her, once curious and friendly, now carried apprehension. Nobody spoke to her. This morning, she too was growing anxious. Heavy expectations weighed upon her. She felt like an athlete about to take a high dive, with thousands of eyes upon her. But the lives of her audience depended on the success of her performance.

The Captain's conference room was up on the West Side three-quarter-G level. An imitation oaken table with a false varnished surface dominated it. The room and the table were an expensive use of the ship's space, calculated to emphasise the Captain's status and power. Gillian was impressed.

On one side of the table, the ship's senior officers, including the Executive Officer, Joan Rubilio, and the Navigation Officer, Mr Dryen, flanked the Captain. Gillian Berry sat opposite with three other non-officers, people she didn't yet know. Gillian noticed the Captain's cane, hanging on the back of his seat. Mr Dryen twisted the handle of his cane between his fingers. 

As the Captain opened the meeting, Joan Rubilio flashed a smile of greeting at Gillian.

"First, thank you, all, for attending. I'm obliged to inform you that this discussion is being recorded." Captain Xing looked around the table in emphasis, then continued, "As you are aware, we appear to be stranded, following the recent disaster with the Walk. But I don't want to discuss a detailed plan at this stage. Our purpose at this meeting is to identify possible options for detailed assessment and planning."

The Captain glanced at Gillian. "The young lady with us today, as I'm sure you recognise, is Gillian Berry, our apprentice Walker. I assume those of you who have not already met her have seen her on the shipboard news."

Gillian shifted and straightened herself in her seat. She felt her face grow hot under the scrutiny of the important people surrounding her. She lowered her eyes and gazed at the varnished tabletop.

"I want to take this opportunity to make a clear statement. We all appreciate the historical tension between Walkers and traditional merchant navy crew, especially navigators. This divide between interstellar and interplanetary navigators can lead to problems, but we can't afford that now. I want to see an effort to reduce this awkwardness. It may impede our vital work." Captain Xing glanced around the table.

"I agree," Mr Dryen said. "My department will certainly give Ms Berry all the assistance we can."

The Captain continued to gaze at him. Mr Dryen added, " - In terms of the navigational and related expertise she requires." He glanced at Gillian, with an odd, half shy expression.

All the officers gave their assurances. As the babble of encouragement washed over her, Gillian could not prevent herself blushing.

Captain Xing continued his introduction, gesturing at committee members as he identified them. "We also have with us Mr Barry, the elected representative of the passengers, and Mr Rogers, our astrophysicist."

Mr Rogers nodded at the group. His face looked nervous.

The Captain made the briefest of pauses before continuing, " - and Mr McWhirter."

The Captain and Mr McWhirter grinned at each other, without humour. McWhirter was a short, stout man who sat uneasily in his chair. Gillian noticed how he rubbed one of his hands across his chin, his eyes glancing from person to person.

"Mr McWhirter is the only government official on the ship. He was at one time the Chief Trouble-maker for the European-Asian block back on Earth. He's now conducting economic and social research. I thought we needed an independent and sceptical figure in our team."

There was a short silence. Then Captain Xing asked, "Any questions or suggestions about other individuals who might help us?"

"Abel Yegg?" Executive Officer Joan Rubilio asked. "We definitely need his knowledge and experience, if he's capable."

The Captain responded, "This is my Executive Officer, Joan Rubilio, for those of you who haven't met her. My latest information is that Mr Yegg is still under treatment. He's lightly sedated, but capable of answering questions if necessary. It's very fortunate for us that he seems to be in a better condition than Mr Dane."

Captain Xing glanced at another of his officers, a woman with jet black hair and dark eyes. "Doctor Morris here wants him to continue resting for the moment. I suggest we should record the questions we have for Mr Yegg."

"I'll coordinate them," Dr Morris said. She wobbled her head as she spoke.

 "Agreed," the Captain said. "All questions are to be sent to Doctor Morris." Glancing around the table to see if anyone else wished to comment, he continued, "I think we should make sure everyone here is up to date on Mr Yegg's condition. Doctor Morris, can you give us the latest on Mr Yegg?"

Gillian saw Dr Morris take in a breath before speaking. "Abel Yegg is now incapable of performing his function as a Walker. And this will be the case, I'm afraid, for many months, if not longer. Our testing indicates that he has lost his capabilities as a Walker."

Everyone at the table glanced at Gillian. Out of habit, she lowered her eyes, but stopped, and made an effort to gaze boldly back at them all.

"But we can get information and advice from Mr Yegg, if we're careful not to exhaust him."

"What exactly is wrong with the man?" Mr Barry, the passenger representative, asked. Gillian noticed a hint of irritation in his voice, as if he suspected Abel might a malingerer.

Dr Morris spread her hands. "It's not clear. He appears lucid when conscious, but he often drifts off to sleep. Physical examination and brain scans suggest a loss of motor coordination. This is his most serious problem, from our perspective. We also have evidence of memory problems. We can't say when he is likely to recover, or if his problems are permanent."

"Is his condition the same as Mr Dane's?" the Captain asked.

"Similar - but nowhere near as bad. Mr Dane is in no position to assist us at all, I'm afraid."

"Well," Barry said, "Can we stay at our current location until Yegg recovers? I understand we can last a long time without running out of air, food, water and so on. Our problems will be impatient passengers, ones with pressing business or family matters."

Gillian had assumed that Mr Barry must be one of the rare earths merchants. But his suggestion about sitting out the problem made her wonder.

Captain Xing responded, "We'll need to complete an assessment of passenger morale before we agree on any course of action. My Exec Officer, Mr Rubilio, is already addressing that task. She will need support, which I will assign for her."

 Joan nodded at the Captain and gave further details in response to Barry's comments. "We can last at least a century with our fusion pile - far longer than is practicable for most of us. We would be prudent to access an external energy source by visiting a suitable star every few years."

"Do we know the cause of Yegg's problem?" Barry asked.

Captain Xing replied, "We've identified a software error." He turned to Mr Dryen, the Navigation Officer.

Dryen looked down at his pad and fingered the surface. "We think an error was introduced during the last software upgrade, before departing Earth orbit. The upgrade included changes to the system's timekeeping functionality. Towards the end of their journeys, our Walkers were receiving inexact location information."

"And?"

"That's what made them trip. After each step, the ship's systems don't have the time to acceptable accuracy. The Walker's steps appear instantaneous to us and to the computers, but they aren't. Each step takes something in the order of tens of nanoseconds, sometimes longer. The system applies a few simple rules or approximations to manage this. But changes in the last software release damaged the function. Now, timing errors accumulate over the course of several voyages."

"When was this problem discovered?" Mr Barry asked.

"We inferred it based on our examination of the logs following Yegg's incident."

Captain Xing remarked, "I presume that the Walker's problems were exacerbated by his illness?"

"That may well be true," Mr Dryen said. He glanced at Dr Morris as he spoke and she nodded.

McWhirter leant forward in his seat. "Mr Dryen, if what you've just told us is correct, do you realise what this means? All other ships with the same upgrade are vulnerable. As we sit here, we may be losing them all, one by one!"

"Can't we get some warning out?" Mr Barry asked. Then he looked embarrassed. "Of course - I'm being ridiculous. It would be impossible." For a moment, his face lost its aggressive appearance.

But his mistake was easy to make. People still forgot that, in these modern times, communications were no longer instantaneous. The speed of light limited all information flows between star systems, and to starships. Government, commerce, and personal communications had moved back to a mode of operation more like the eighteenth century than the twenty-fourth. All communications were limited by the speed with which starships could travel by Newtonian means to their planetary destinations, once the interstellar Walk phase of their journey concluded. Massive electronic data transfers occurred on entering a planetary system.

McWhirter said, "I'd like to examine this problem in detail, when you're available, Mr Dryen."

"Certainly," Dryen replied. "I'll send you a copy of the report first."

McWhirter glanced at Gillian. "Has Ms Berry seen this document?"

"I have," Gillian said. This was the first time she had spoken, and, again, all the committee members stared at her. Overwhelmed, she lowered her eyes in confusion and wondered if they expected her to offer an opinion.

She had read that the visual information, and other sensory cues presented to the Walkers, had grown misleading. When Walkers saw or felt something, the object's perceived position was imprecise, due to the timing error. To a limited extent, Walkers were always stepping blind. At the end of their journey, entering a planetary system required much more accuracy in their navigation. But accumulated positional errors grew too large. Related perceptual and other disruptions also caused significant medical problems.

Dryen concluded: "We also discovered a second software problem, worse than the timing one. When the software crashed, it recovered straightaway, but failed to detect Mr Yegg's fall - and this was a big, big fall. You saw him rolling, and that caused all sorts of scale-changing problems because some of his random movements were interpreted as command gestures. The error may have been in the software for a long time, but no fall by a Walker has been severe enough to encounter the problem until recently. In effect, the system didn't understand the information presented to it."

These two explanations, though frightening, provided relief for Gillian. She had grown nervous about the possibility of something malevolent in interstellar space, after hearing the rumours following Mr Dane's accident. She remembered Abel looking behind him as if he was being pursued, and that final lurch: almost as if something had thrown him.

"It's lucky we didn't jump straight into the sun!" McWhirter murmured.

"Can we fix this software problem ourselves, somehow?" Barry asked.

Dryen replied, "We're examining the possibility of going back to the earlier software version."

"Will we lose anything important from the current version if we revert?"

"That's what we need to look at."

Captain Xing turned to Mr Rogers, the astrophysicist. "Even assuming our Ms Berry here can be made ready to stand in for Abel Yegg, I understand you still see another significant problem. Mr Rogers?"

The astrophysicist was the only person in the room to look nervous. He answered: "As we all recognise, the incident, whatever the cause, sent us shooting across a huge distance. We've left the local bubble, we're in a place no ship has ever been before."

"What's the problem with our location?" Mr Barry asked. "I've heard of the 'bubble', but I'm not familiar with the details."

"Our solar system, and all the star systems inside the zone of human occupation, occupy a volume of space about fifty light years wide. This volume lies within an area about 300 light years across called the local bubble. It's a hole in the dust and gas clouds in our region of the galaxy. The dust and gas density inside our bubble is about one tenth the density of the surrounding clouds."

"And there's a problem with this?" Mr Barry asked.

Gillian glanced at him. Barry's face wore a querulous expression, as if he was annoyed or suspicious.

"So far as we're aware, no ship has ever left the local bubble. Nobody has ever conducted a Walk within such dense gas and dust clouds. This is a completely new environment."

"When you say dense," McWhirter commented, "it's still pretty close to a vacuum to most people, isn't it?"

"Certainly. But we may find problems in such a novel environment, for everyone as well as for Walkers. For example, we may face a higher rate of nano-blasts during a Walk, perhaps reaching dangerous levels. There may be increased wear on the ship."

"And we might all get cancer."

"That's the least of our possible problems, I hope. We must put in significant effort studying and mapping these clouds, before we attempt a Walk."

Captain Xing said, "If we stay here, hoping Mr Yegg or Mr Dane recover, rescue is impossible - even if our location were known." He glanced around the table. "Walking back is, I presume, our main option. But we can't attempt that yet, because Ms Berry here must complete a suitable training course."

The table fell silent for a moment.

"How long will the training take?" Barry asked. "Can we shorten it?"

"Abel Yegg advised me, when he identified her as a suitable candidate for Walking, that up to two months is needed for her gain the basic knowledge and skills she needs. That is, sufficient for her to conduct a supervised walk."

Mr Barry remarked, "Well, there's nobody to supervise her now." He added, in the querulous tone that people were becoming familiar with, "Surely we can find some way we can speed up the training? Cut out the superfluous stuff, focus on the core capabilities?"

The Captain replied, "I made just that comment on the day Mr Yegg gave me his estimate. Mr Rogers and Mr Dryen are working with Mr Yegg, as and when his condition permits, to do exactly what you suggest."

"Good!" Mr Barry exclaimed.

McWhirter said, "I assume we'll be identifying more Walker candidates to train up? We've got several thousand passengers on board, so surely we can find some suitable people." He glanced at Gillian. "We've already discovered the problems of having only one Walker."

Gillian liked this idea; she would not be alone in her responsibilities. She would have friendly work colleagues. But she noticed the implication that she could also face danger.

McWhirter added, "And I would really like to put on that mask and try out the Walk simulator myself."

Everyone laughed, out of politeness, but Gillian detected a nervous edge.

Captain Xing said, "So, we either stay where we are, and live out our lives, or we start Walking. I don't think the first option is acceptable, or even practicable. I don't see any other alternatives than attempting the Walk back." He glanced at his Executive Officer, then around the table, and finally, at Gillian.