The sound of the house door tone sliced into Amber's hearing, tearing her away from her homework. She tapped her stylus against her desk for a moment then elected to let someone else in the family answer it. Scribbling away she returned to the mathematics. The incident with the boy at school had upset her normal sense of equilibrium, so she buried herself in work to try and divert her restless thoughts. She breezed through the complex equations, barely stopping as her mind reorganised the array of numbers and letters. They were calculations of interstellar dynamics, navigational computations of the kind processed by spacecraft.

Amber could do the maths almost as quickly as the average navigation system, something her teachers had been swift to flag up. She was currently on the fast-track to early entry into Illuvari's naval academy – two years at most. Her screen flickered as she worked her way down the lines of deduction, shutting off the outside world.

That is, until her mother shouted her name.

"Amber, can you come downstairs please?"

With a resigned sigh she tossed the stylus onto her desk and stood up. She stepped out into the hall and walked to the head of the stairs, looking down to the front door. Her mother stood off to one side revealing two boys her age. Her heart juddered in surprise. She instantly recognised the new pupil from school, the boy she'd seen on the bus, the one who'd been looking at her with such curiosity, shadowing her so strangely and had disappeared without a trace.

He looked different now though, clad in a jet black hooded top, dark canvas trousers and thick-soled boots. A silver band hung around his wrist, surmounted by a blue oval like a glowing sapphire. His companion was taller, clad in identical clothes and his dark hair was clipped short. A small skeletal rig held a rectangular transparent plate over his right eye that was riddled with barely visible lines of blue.

"Amber," her mother began uncertainly. "These two...gentlemen say they need to talk to you."

The boy from school stifled a laugh. "Eh, I wouldn't say we were gentlemen, Mrs. Garret, just two guys trying to do a job." He looked up the stairs and his smile faded. "Amber, we need to have a talk, in private."

"Who are you people?" Amber said, not moving from the head of the stairs.

"We work for a branch of the Interstellar Exploration Fleet."

"I know they seem awfully young," her mother interjected, worry and confusion thick in her voice. "But their identification passes confirmed it. I think you should speak with them."

"What's this about?" she demanded.

"Amber please-," the boy raised his hands in placation, "there is nothing sinister about what's going on here, but it is important. We need to talk to you alone. It's a security matter."

Reluctantly she descended the stairs, eyeing the two teenagers suspiciously. She stopped in front of them and folded her arms.

"Well?"

"If we could step outside?"

"Why?" she demanded.

The larger boy bristled but his companion smiled ruefully. "I know you don't like this. Believe me, I know exactly how you feel, but what we have to discuss is highly classified. We can't talk about it in front of your family."

"Amber, it's alright," her mother said. "Just speak to them for a moment. We're right inside."

She pressed her lips together tightly and gave a stiff nod. The boy opened the door and gestured for her to go first. Stepping out into the evening air Amber hugged herself as a gentle breeze swept through the street. Perfectly rectangular strips of grass lined both sides of the street, each one planted with four trees rich with green leaves. Globular white gravity lights floated above the neighbourhood to illuminate the night.

She turned to face the two boys. Despite herself she reluctantly admitted that Halley might have had a point. Up close, clad in the smart black of whatever organisation had sent him, the boy was attractive in a mysterious sort of way. Still, her immediate concerns lay elsewhere.

"Okay," she said. "What do you want?"

"My name is Darien," he replied and gestured to his hulking companion. "This is Idas. We represent a very, very special organisation."

"And what do you want with me?"

"Amber, how much do you know about Blink?" he asked.

She frowned. "It's a form of instantaneous interstellar travel, allowing the individual to open a kind of spatial short cut between two distinct points in space-time. It's a biological characteristic inherent in less than a thousandth of a percent of the human population."

"So, quite a lot," Idas grunted.

"I do my homework."

"And then some," Darien chuckled. "Blink is what keeps human civilisation connected and what lets us respond to threats on the outer edges of colonised space. The fastest ships we have take months to reach the outer rims. We use Blink travel as a first response tool."

"We?" Amber said.

"Yes, 'we.' Idas and I are Blink operatives."

"But...but you're just kids!" she exclaimed.

"So are you."

"Shut up, Idas," Darien snapped, elbowing his companion in the ribs before addressing her again. "What you won't find in your textbooks is why Blink operatives are people like us. Blink travel is not as simple as just thinking about where you want to go and just appearing there. People have a small window where they can Blink effectively. It starts when you hit adolescence and if you're lucky you'll get ten years maximum. After that the body starts rejecting the process. The worse it gets the less precise and more dangerous your Blinking becomes. Which brings us to why we're here..."

"What?"

"Amber, I've been keeping an eye on you for a while," he continued. "You've got all the characteristics."

"Nope." She shook her head. "Save it. I'm not going anywhere. I've got a life of my own and it's going pretty well, thank you very much."

"You can do a lot better than the navy," Idas grated. "Being a Blink operative is about as high up the tree as you can get. We've got access to all your test records. Top of the class, straight A student, never dropped a mark, learning aptitude off the charts – even by our standards you're exceptional."

"I'm flattered," Amber shot back. "But I've got everything I want here. I'm not getting jetted off to some facility out in space and never seeing my family and friends again!"

To her amazement, Darien started to laugh.

"Sorry," he said, fighting to control himself. "It's just, it doesn't really work that way. We're not some evil organisation who are planning to lock you away in a secret lab on the dark side of the moon. We're the good guys Amber. I won't lie – it's a dangerous job, but they can make it worth your while. This isn't the rest of your life. You can only be part of Blink for ten years, maximum and that's only if you decide to extend your contract. You can finish with Blink and go back to whatever life you want. You'll be given leave every year to return home, visit family, catch up with friends, and the pay is...substantial."

"I don't need more money." She took a deep breath, the enormity of what the mysterious pair were proposing beginning to set in. "I don't want to go off out into space to be some kind of super-human police officer. I just want to get on with the life I chose."

"I understand your reluctance," Darien said. "I really do. I was exactly the same when they came to find me, but it's worth it. Trust me."

"Trust you? I've never even met you."

"You need to think about the big picture," he continued. "Being a Blink operative means you are helping everyone, and I don't mean everyone on this planet. I mean everyone on every colony, everywhere. You are a blip among billions, Amber, one of the few who've got the gift, and one of the fewer still who have such a natural talent to use it. We need you."

"There must be others..."

"Oh, we have plenty who are more willing," Idas chipped in. "But none who are quite as able."

Darien took a step towards her and he spoke gently. "Look, you don't have to give us an answer right this second. I know this is a lot to swallow all at once." His face softened and he pulled something from his jacket pocket. "Just do me a favour. Look through this data chip. It'll give you all the details about the contract, about where you'll be working. It's keyed to your genetic print so no-one else in your family will be able to open it." He handed the tiny metal cube to her. "We'll be in the area for the next little while. Call the number the chip gives you when you've made up your mind."

Amber stared at the chip, unsure of what to say. This tiny, cube, millimetres across, could decide the course of her life for years to come. "What if I say no?"

The boy looked at her sadly. "If you say no then Blink will lose out on one of the most promising recruits I've ever seen. No harm, no foul."

"You could be out there saving lives every day," Idas rumbled. "If you'd rather throw away your gift to spend your life navigating freighters and tugboats then you need to take a long hard look in the mirror, because you have a problem." He shook his head in disgust and stomped away. Amber's mouth opened and closed in shock at his outburst.

Darien hunched his shoulders awkwardly. "You'll have to forgive Idas. He's a good operative but he's no diplomat."

"I...it's not that I don't want to help people-"

"I know that," he said. "I never said you didn't. Idas just has a very black and white view of the world. Still, he has a point. Running shipping lanes and navigating ships is a waste of your skills, Amber. You can do so much more. All I'm asking is that you think about it." He smiled. "Hopefully I'll see you soon." He closed his eyes and the air around him seemed to tremble and shake. Then, with the suddenness of a balloon popping, he vanished.

Amber felt a ripple of force wash over her and she stumbled backwards with a yelp of surprise. She tripped and fell against the front door of the house, staring in disbelief at the empty void of space where Darien had been standing only seconds before. The air still shimmered with the aftermath of his disappearance, as though the space itself was still reacting to his sudden absence.

She slowly pushed herself back to her feet, still looking at the disturbance. She'd never seen anyone Blink-travel before, but she had an inkling that Darien had just shown her first hand. Stepping forward she reached out one hand towards the shimmers in the air. Her fingers brushed against it and she felt something like an electric shock rush up her arm. It didn't hurt – she suddenly felt distant, detached, struggling to concentrate.

Then images began to swim in her mind's eye. She could see the interior of some kind of ship, its metal walls and bleeping consoles. A strange glowing rod stood in a separate room and two dark, shadowy figures moved back and forth. Muffled voices thumped in her ears like deeply distorted drums, rising and falling in bizarre peaks and troughs. The noise surged until she felt a band of pain rise behind her eyes.

She instinctively jerked away.

Looking down at her hand, Amber's eyes widened in surprise. Just for a second her arm seemed to be partly transparent and she could see the smooth concrete pavement below it. It solidified quickly, however, leaving only a strange, fizzing sensation on her skin to remember it by.

Unfurling the fingers of her other hand, Amber looked down at the data chip and swallowed hard. It was time to make a choice.