Author: Chris Cook
Rating: PG-13 (mild violence)
Copyright: Based on characters from Buffy The Vampire Slayer, created by Joss Whedon and his talented minionators, and Tron, by Steven Lisberger. All original material is copyright 2003 Chris Cook.

The manta-ray rocketed along its transit beam, the landscape of the open system a blur beneath it. Inside, in a cockpit designed for a single program, Willow was curled up to Tara's side. Tara kept one arm around Willow's waist, using her free hand to make occasional adjustments to the simulation. Willow just watched her, in comfortable silence, content to study Tara's expression of concentration as she steered the craft, and the occasional warm smiles as she glanced sidelong at Willow.

"Did I mention how amazing you are?" Willow murmured.

"Seventeen times so far," said Tara with a grin. She made a few final adjustments to the manta-ray's controls then shifted in the pilot's seat, rolling over to face Willow.

"You saved my life," said Willow quietly. "I mean, you already have, against Rain, and escaping from the Game Grid, but... you came through an army to save me, that's, well, here I go saying 'amazing' again."

"You made me this way. Not like that," Tara added hastily, seeing the frown on Willow's face, "when I first activated I wasn't capable of fear, or doubt. Or love. But I grew, I changed. And when I found you, when we came together... when we achieved unity," she said shyly, "that's how you made me what I am. You were in danger... I would have followed you anywhere. If I hadn't," she shrugged, "I wouldn't deserve you."

"You make me sound like I'm... perfect, or something," said Willow, brushing a finger over Tara's lips.

"I think none of us are perfect," said Tara thoughtfully, "not programs, not even users. Not even my Willow," she added, nipping playfully at Willow's finger then releasing it. "But if I believe my Willow is perfect anyway... it seems I'm capable of contradictory beliefs." The corners of her mouth quirked up in a wry grin. "I'll manage."

"We'll manage," laughed Willow softly. "I am, you know."

"What?"

"Yours," Willow said, utterly sincere. Tara stared at her, as if mesmerised.

"I could say the same thing," she whispered.

"I remember you did," said Willow, "in... rather intense circumstances," she blushed.

"I know," Tara said. "I meant every word."

An alarm broke the silence that descended on the pair as they leaned closer. Tara heaved a frustrated sigh and glanced at the controls. Her expression grew serious in an instant.

"We're approaching Echelon," she said.

"What's our plan?" asked Willow, all seriousness.

"This transit should bring us past the perimeter and whatever shield walls it has in place," said Tara, "but we can't expect to get all the way in. No-one knows exactly what Echelon has become. GDI's analysis indicated that it had absorbed so much code it had become like a network. We may actually have to go inside Echelon itself."

"If we do, we can deactivate it?"

"I've got a set of fragmentation codes on my data disc," explained Tara, "GDI put them together as a last resort. And some of the programs we brought from the I/O tower escaped from partitions that were close to Echelon when it all began. They helped GDI customise these codes. According to what they heard, Echelon gains power by absorbing other programs. It destroys them as programs, but leaves their functionality intact. Even the soldiers aren't quite separate programs - even when Echelon allows a program to survive, to serve it, it makes them a part of itself."

"So we're going to cut it off?" asked Willow. Tara separated her disc from her back.

"We have to get this disc to the core of Echelon," she said, "to the original Echelon program, what it was before it began taking over everything around itself. Normally it would be invulnerable, the combined power of all those programs is too much. The codes on this disc will break the links between that original Echelon and everything it's absorbed. It'll be vulnerable, for a fraction of a millicycle, just like any other program."

"And then?"

"We terminate it," said Tara darkly. "There's no other way. Even if it's deactivated, the influx of power from its slave programs would revive it the instant the links reconnect. We have to terminate it."

"Tara, I'm sorry," said Willow quietly. She dropped her eyes, unable to meet Tara's questioning gaze.

"What for?"

"It's my fault you're doing this," Willow admitted, "I created you to shut down Echelon. I wish there was another way-"

"There isn't," Tara insisted. "I don't want to terminate any program, but this is the only way to free the system. And it's not your fault. If there was some other way, I'd defy the instructions you gave me." Willow looked up, with the beginnings of tears in her eyes.

"Promise?" she said.

"Promise," Tara assured her. She checked the controls again.

"We're close now," she said, "remember, be careful, and stay with me. There's never been a program like Echelon before, not even GDI knows what it'll be like in there."

"You bet I'll stay with you," said Willow earnestly, "I'm not letting you out of my sight!" Tara smiled back at her.

"Promise?" she asked.

"Promise," said Willow with a grin. Tara hugged Willow, then rolled back over to pay full attention to the manta-ray's controls.

"We're about to come out of transit," she warned. For a moment Willow saw a silhouette looming on the horizon, then it was as if a storm cloud had passed over the sun. The manta-ray vibrated as it slowed to normal motion, in front of a monumental structure, an artificial mesa hundreds of miles wide. Willow stared up at the solid, sheer cliffs, miles high, with trails of power running up over them like waterfalls in reverse - drawing power in, instead of letting it flow outwards. Ahead of them their beam vanished into the shadows of a huge chasm in the cliffs. Ribbons of power crackled across the gap in the cliff, lightning discharges in which each bolt was itself thicker than the manta-ray, and brighter than the sun. The energy whipped violently through the entire length of the chasm, as far as Willow could see into the shadow, and perilously close to their transit beam.

"It's alright," Tara said reassuringly, though Willow could her the awe in her voice, "they won't hit us."

Willow shrank back from the transparent canopy of the manta-ray regardless, pressing herself up against Tara. The simulation moved slowly along the beam, with enough energy to vaporise it crackling barely metres away. In between flinching from the discharges, Willow stared out at the walls of the chasm, seeing them grow more jagged and irregular the further they went. At the point where it cut through the giant cliffs the chasm had been perfectly smooth, like a knife had sliced it out of the landscape, but now, further in, there were forms emerging from it, things that looked like huge power conduits twisting out of the walls, crossing each other like a massive lattice.

At last they emerged from the canyon, but not into what passed for daylight in the system. Looking up, Willow saw the sky covered by dark structures, semi-opaque sheets of blackness with muted flashes of energy pulsing within them. Beneath this ominous sky the ground rose up, miles high, a giant mountain drawing all the power in the system into itself. Willow saw power feeds the size of buildings snaking up the sides of the structure, but as she cast her gaze out across the landscape it all blended together - it was too big, and all she could see was the single, vast shape rising up towards the heavens. At its apex was a volcanic crater, pulsing with red energy, emitting a plume of pure darkness, like a cloud of ash, with raw power writhing inside it. It was a living thing, huge and malevolent.

"Is that..." whispered Willow.

"Echelon," confirmed Tara.

Their tiny craft drifted along its beam, towards the mountain until all Willow could see through the canopy was Echelon's massive form, and the turmoil in the ash cloud above it. Finally they were close enough to see their destination, a great archway set into the side of the mountain. Lit by only the beam, Willow could just make out the shapes of huge buildings inside, towers taller, more massive, than anything she had yet seen. As the manta-ray crossed the threshold of the archway, the beam vanished, plunging the interior of Echelon into darkness again. Willow felt Tara shiver as their craft passed into the shadow, drifting slowly down to land in darkness.

Once grounded the manta-ray's hull split and folded in on itself until it had become a hollow skeleton of its previous form. Tara took Willow's hand and helped her clear the sharp edges of the craft, barely visible in the light from the archway behind them. Neither of them showed any inclination to release the other's hand once they stood in open ground, facing the blackness ahead of them.

"We should hurry," said Tara quietly, "Sark and Rain won't be far behind us. They must know what we're trying to do, and Echelon won't place any goal above preserving itself."

"At least they'll leave GDI alone," Willow suggested.

"That was the plan," said Tara.

"Can you see anything?" asked Willow.

"Not enough," Tara answered. She glanced over her shoulder at the archway, then turned to face the darkness again. "We go straight ahead," she said, "the real Echelon will be at the heart of all this." They set off, hand in hand, into the shadows. Willow kept glancing over her shoulder, at the archway - the light was inviting. With every step they took, it seemed to die a little more, as if the air had darkness suspended in it. After a few minutes, Willow couldn't even see the arch, and had to rely on Tara's sense of direction to know which way they were going.

"Tara, I'm... scared," she admitted. Tara gave her hand a reassuring squeeze.

"Me too," she said. "But we have to do this."

"I know," said Willow, trying to sound more sure of herself. "If there was any light, you'd be able to see me looking very resolute right now."

"I can imagine," said Tara. Willow heard a little more happiness in her voice, and smiled.

"It'll be alright," Tara spoke again after a moment's silence, "I'll protect you. I won't let anything hurt you."

"I know," said Willow. "Tara?"

"Yes?"

"If you turn around, will you be able to remember which way is inwards?"

"Yes, why?" asked Tara. Willow took Tara gently by the waist, turned her around and kissed her.

"I love you," she whispered into Tara's lips.

"Unity," said Tara softly, "I love you."

"Don't let anything hurt you, either," Willow warned.

"That's the plan," said Tara, taking Willow's hand again and leading her on into the heart of Echelon.