The first two days had been the worst.

As he hid in the ducts, that first night he had cried softly to himself, consumed by hunger pangs. No matter how hard he tried, it was a constant nagging reminder. It was reminiscent of the HUD virus his sister had infected him with when she was four, except there was no shot of anti-malware available to cure it.

Desperate, he had tried cutting off bits of his suit with the small pocketknife, his father had given him for his last birthday. However, the material proved to be inedible, although the constant chewing did keep his mouth moist.

By the second day, his limbs were lethargic and his head swam in a sea of unfocused thoughts. It almost cost him his life.

He had been crawling through one of the side ducts in Blue Sector. He had been unable to escape to somewhere better. The Grownups seemed to be everywhere. Even if they couldn't reach him secreted away in the vents, they always seemed to know where he was.

As he tried to find a way out, he passed through a winding duct near Medilab – it had a distinctive smell. There was a grate in the floor of the duct. He made the mistake of crossing it without checking first. Galan had been waiting beneath it.

Dru was almost across when Galan's hand snapped out from between the slats and grabbed Dru's left ankle.

"I've got him!" Galan had screamed.

Dru squirmed and tried to break away, but Galan's grip held fast. He began to squeeze and Dru cried out in pain.

Dru kicked out with his free foot at Galan's hand to break the hold, but Galan reached his other arm through the grate and tried to grab that one.

"Quick, Gin!" Galan cried.

In desperation, Dru did something he had promised his father he would never do. He used his knife to cut someone. In fact, he plunged it right into Galan's right wrist.

With a cry, Galan had yanked his hand away taking the knife with it. Dru quickly scrambled along the vent and escaped, although Galan hunted him for a good many hours afterwards - constantly cursing his name.

It was the day after his escape from Galan when he made the realisation.

He was still stuck in Blue Sector. The Grownups had doubled the patrols now they knew where he was. Then he had heard a noise behind him. Someone else was moving around.

"Dru, we don't want to hurt you," a voice had called to him. "Your mummy and daddy, they miss you." It was one of the Brethren Mothers: Manda.

She was at one end of a long duct, and Dru was at the other end. He didn't bother to respond. Instead he scurried away.

She chased after him but despite being petite, Manda found it difficult to crawl through the ducts. He could hear her grunting and cussing as he lost her amongst the maze of rapid turns and double-backs.

They were closing in. It was only a matter of time.

He wanted to know how they were tracing him. He knew he wasn't making much noise. They could have traced his heat signature, but he knew most of the sensors in Blue Sector were offline. His father had complained about it constantly before the Internment. Had they fixed them just to find him?

Then he remembered something Gar had revealed to him more than a year before.

"They can track you with it." Gar said.

"What? My HUD?" Dru had asked increduously. HUD meaning his Heads-Up Display, the augmented reality system that provided a wealth of information and perception modes.

"Yeah. Everything you see. Everything you do. They know what you're thinking. That's the only way they could have known I was going to wag school."

"You always wag school!"

"But I only thought about it this time."

Gar said a lot of things that weren't true, and so Dru had dismissed the idea at the time. However, alone, and trapped in a closing net he re-evaluated the thought.

Were they tracking him through his HUD? Could he even survive without it? He'd lose access to the map of the tunnels he'd made.

He knew everyone was implanted with a transponder in utero. Explosive decom was an ever present reality of Col life. In school they had been told the transponders would allow the rescuers to find them. However, everyone soon worked out they would just allow fast retrieval of the frozen corpses. That was understandable. The war meant that there was no room for sentiment: every resource was valuable.

Knowing that he could be tracked with it, he had Meri carve out his transponder using his pocketknife. She managed to extract the Node easily enough, but the roots kept regenerating. The transponders were one of the few organically based technologies they could still use. It took multiple tries but in the end he made her heat up the knife until it was coated with black carbon, then use that the sever and cauterise the roots before they could regenerate.

The operation had hurt mightily, but he knew that he had no chance of escape with it attached. Meri had tenderly patched him up later ensuring that there was no chance of infection.

"For Chocolate," she had said kissing him on the cheek when she was done.

He smiled back at her. "Just a precaution" he'd said.

"Say hi to your rats for me," she said displaying some of their mother's insight.

Dru hadn't told Meri what he was planning. He didn't want her worrying. Yet she had guessed correctly anyway.

That had seemed liked weeks ago.

He considered what Gar had told him. Would he even be able to see without it? The HUD gave him access to a number of viewing modes, allowing him to see no matter how dark the room. He could even seen through smoke.

His helmet had a small lantern attached. Would it be bright enough? Did it even still work? It was only supposed to be used in emergencies and he'd never tested it before.

Dru triggered the lantern. It worked, sending out a narrow beam reaching out to about three or four metres. Not great, but perhaps good enough. A bright light might attract attention of its own.

Then he heard Grownups nearby. Not close, but at the same time too close. This was as good a time as any to test Gar's theory. Dru turned off his HUD.

It was unsettling not having access to the constant supply of information. It was dark in the tunnel (even with the lantern) . He sat for a time, just listening to the sounds of the Col. The Grownups were moving away. At least they weren't getting any louder. Perhaps Gar had been right.

He initially found the going difficult. Without the map he quickly got lost and fumbled uselessly in the ducts for hours. He was already starving by then, but he continued climbing up and down the levels.

Occasionally he would hear someone in one of the nearby corridors or rooms. He would stop and listen, sometimes peering through the grates to see if he could spot anyone. He never did and they never once seemed to notice him.

Then he happened upon an exit leading from Blue Sector. It was unguarded. The first time he had ever found one without anyone nearby. Normally they were waiting for him. That confirmed it. Gar had been right.

Dru took his time, ensuring it wasn't a trap. Then he quietly slipped out into Green Sector. He had escaped.