Revenge.
Ink wanted revenge for what happened to Cure.
Error was pretty surprised, actually. Typically it was him who wanted to wreak havoc on others, unlike Ink. However, he wasn't about to complain.
"I'm with ya, but how are we supposed to get there and back?" he questioned.
"Easy. Nightmare and Fell will help us."
"How?"
"I'll show you."
After creating a portal with a slash of his paintbrush, Ink shoved Error through. He managed to stumble on the other side of the portal, then proceeded to trip and faceplant on the pavement. Ink stepped over him, then extended a hand. Error didn't bother accepting it, only teleported upright and offered Ink a brief glare.
Ink took them to Grillby's, although it looked different to Undertale's normal pub. The floorboards were scratchy and a strange shade of violet, the walls were dark and stained with who knows what, and at the bar stood an odd version of Grillby - who's flames were the colour of lavender. He didn't have any glasses, only fierce, empty white eyes, a rude yet playful smirk, and wore a formal suit with fur on the shoulders and around the neck.
Sitting at the bar were a few grim-looking monsters, one skeleton, and a human. Ink approached the skeleton soundlessly, dragging Error behind him, then pounced.
The skeleton jumped in his seat and spun round, huge sharp teeth bared, his gold tooth glinting. Scruffy fur around his black jacket bristled, and the black, spiked dog's collar around his neck rattled.
"Hey Red!" Ink said in a way of greeting Fell.
He barked roughly, "I hate you."
"Having trouble, Sans?" Underfell's twisted Grillby sneered, as he spat in a glass and rubbed it with a dirty cloth.
"C'mon, we need your help," Ink sighed, before grabbing Fell's wrist and trying to lead him away, as he was currently doing to Error.
Fell twisted away, eyes narrowed, his coat rustling with unease. "With what?"
The human sitting beside him; an attractive girl with shoulder-length tawny brown hair and pale skin, wearing a tight red jumper, tilted her head slightly at Ink, with the air of a curious puppy. She didn't say anything though.
"It's really simple, but I'd prefer we talk about it outside," Ink replied. His eyes - one emerald green and the other highlighter pink - shifted to the girl in the seat beside Fell. "Frisk can come too, if you like."
Error realised that his shoulders were tense, and that his jaw was clenched. He quickly relaxed them, trying not to look as uptight as Ink had once said he was. Error was cool. He was chill. Yep. At ease. That was Error. 100%.
All of a sudden, Ink reached forwards and snatched the short chain hanging off of Fell's collar. "I will lead you like a dog if you don't come," he threatened, grinning cheekily. Error rolled his eyes - it was such an Ink move.
With a heavy, exasperated sigh, Fell stood up, and Frisk slipped out of her seat beside him. He yanked the gleaming chain out of Ink's hands and followed him as he led the party to the door.
"Oi! Pay up!" Grillby yelled from behind them.
Nobody answered him.
Ink peered at Error, then told the three to listen up, as soon as they were outside on the street. "Do you know where Nightmare is?"
"Who's Nightmare?" Frisk demanded, her voice sharper than Error had expected.
"Nightmare!Sans is this bad dude that's fueled by negative emotions," explained Ink swiftly.
Error thought for a moment. "I saw him earlier," he mumbled. "But I don't know where he went."
"Where did you see him?" demanded Ink. Inside those eyes of his - with a blink, one pupil had become a golden star and the other a sky blue circle - sparkled something like suspicion.
Hesitantly, Error answered, "In my AU."
Fell squinted at Error. "I thought you destroyed your AU,"
"I did."
Silence. Ink broke it by saying, "Anyway, we need to find him. Anyone have any ideas?" he looked right at Error as he said that.
"Oh," Error felt himself glitch a little harder than he usually did. "I think he might still be looking for Dream."
Ink bit his lip and suddenly seemed to find the floor extremely interesting.
Bitterly, Fell swore. "What's wrong with Dream?"
"He's corrupted," said Error, darkly.
Frisk's gaze was torn between the three of them. She remained silent, even when Fell nudged her slightly with his elbow, soundlessly wanting to know what she thought of all this.
Once Ink had recovered, he murmured, "That's why Nightmare is gonna help us. Because there's something in it for him. And I think I might know where he is."
"Really? Where?" Frisk wanted to know.
"Dreamtale."
...
Surprisingly, Fell and Frisk had agreed to accompany them to Dream and Nightmare's AU. Unfortunately, Fell didn't have inter-AU teleporting, so he had to step through Ink's portal, and he didn't seem too happy about that. Especially when Error created his own glitchy portal beside Ink's, and Frisk stepped into the glitch. She was unharmed on the other side, yet the overprotective, shorter skeleton still insisted on checking. He also wanted to know if she was cold and if she wanted his jacket, which she politely refused.
It was so unlike Fell to offer his coat, to be chivalrous. Ink had to smother a giggle.
Before them was the surface world, full of rolling emerald hills, sunny blue skies and fluffy white clouds - save for the dark spot on the edge of the horizon, a foreboding shadow, waiting to pounce.
The Tree of Feelings.
Ink huffed inwardly - he hadn't quite got the right coordinates, and they'd landed themselves a few grassy hills away. Throwing a sideways glance at Error - the skeleton who made him actually want to live - Ink guessed the coordinates for the Tree of Feelings and prepared to open a second portal to it. Judging from the looks on the faces of the others, they were also planning on doing the same thing, just in their own ways.
Error met Ink's gaze, and his skull shone in the strong sunlight. Behind him, jade blades of grass wavered and danced in the wary winds from the South.
Something, something inside his ribcage that felt like a soul but surely couldn't be, thumped with pleasure at the sight of Error's face, not glaring, not scowling, not roaring in pain or anger. It thumped with the thought that he was staring at him, that Error offered the ghost of a smile on that dark-toned skull of his, the blue leaking down his face and sliding over his cheekbones purely gleaming, his unusual pupils twinkling like the stars in the sky. Ink felt himself shiver as he recalled the time that he'd been overwhelmed - and he'd drank far too much of the dreadful pink vial. He preferred not to think about that.
Ink's portal opened up with a slash in the air of a sapphire blue paint– matching Error's blue strong truly by accident, and as Ink leapt through, he saw Error glitch away and Fell disappear in a beam of bright scarlet light with Frisk clinging to his shoulder.
They made it to the Tree of Feelings unharmed, but all in slightly different places and all at different times. Ink noticed that he'd arrived last, and he'd guessed the coordinates nearly exactly right. However, Error had underestimated the distance, and ended up standing atop a hill about a kilometre away, while Fell had overestimated and landed right on top of a branch of the tree, with Frisk wobbling uncertainly beside him.
Sure enough, on the other side of the tree, Ink spied a looming shadow.
"Nightmare?" Ink called, warily, wandering around the tree without offering help to Fell or Frisk.
The cursed, corrupted skeleton spun on his heel and glared fiercely at Ink. "What do you want?" he hissed.
Error managed to glitch himself right to Ink's side, and the pale-boned skeleton almost jumped at his sudden appearance. Yet Ink forced himself to relax - they were friends again.
Friends.
Something inside of Ink seemed to claw at his ribs and his spine. Shh, he told the monster inside him. The last thing any of them needed was Ink going nuts in the middle of Dreamtale.
Since Ink had been too distracted to speak, Error had answered for him. "We wanna make a deal."
Shaking himself to loosen those tight bones of his, Ink flashed Nightmare a sly, lazy grin. "Your teleportation skills... for Dream."