A/N: Kinda felt like writing something for this anime since it's amazing… so here we are! I guess it's meant to be a little sad, but hey, there's a sad ending. What do you expect? XD

Dreams are beautiful yet horrifying things...

Nagisa was lying on the grass. His body felt cold and stiff. His skin prickled as he heard screams of familiar voices…

They can show you your deepest desires or your worst fears...

Nagisa gazed at the scene around him. His teacher, Korosensei - the one that wanted to destroy earth - was battling Yanagisawa. Nagisa felt so dizzy and sick. He only see blinding colours, moving tentacles, and the darkness of the night sky. Nagisa hated this feeling so much, yet even feeling mad was draining his energy.

Sometimes, they can bring you great happiness..

Nagisa wanted to do something. He and his classmates had to be the ones to assassinate Korosensei, not the government, not Yanagisawa. But he felt so sick…

Other times, they can destroy you completely…

Nagisa frowned, gritting his teeth. His pale blue hair was swept across his brow. He was covered in dirt and grime. His body felt limp, like he was a twig that could snap at any moment. But he wasn't going to die like this.

Sometimes the dreams of great sadness are far worse than nightmares.

Nagisa, feeling determined, forced himself to sit up. He blinked furiously, trying to knock the sense of vision back into his eyes. He saw his classmates watching the battle with horror. Kayano looked like she was contemplating something. Why did that gave Nagisa such a bad feeling?

"Kayano…" he croaked. He could barely make a sound. It made him feel awfully ashamed. Why did he feel so weak? He examined himself. He didn't look any different…

Kayano - or Yukimara, should he say - leaped in front of the tentacle thing… Korosensei… Nagisa was getting blurry vision again. He covered his right eye with a hand, biting his lip. He felt like lying down again…

But he couldn't. People were in danger.

"Not today." Nagisa muttered under his breath. He forced himself to not only sit up, but stand up. He clenched his fists. He pulled out the green knife. His legs trembled and his heart raced. It felt like he was going to fall down again.

But Nagisa refused.

He took a step, his body screaming in agony. But Nagisa didn't care. His hair blew back in the wind. Lights almost blinded him. But he managed to limp over to his fellow students, his chest heaving. Sounds surrounded him like a gate. It was like the world was a tornado. He weakly clenched his fists.

But he was too late. Kayano was dead.

"No…" he croaked. He frowned. "No!" His vision became dizzy again. His classmates were staring at Kayano, who was dead. Her body was lying on the burned grass. Yanagisawa was cackling. Nagisa stared at her, feeling horribly guilty. He knew - somehow - that this would happen, yet he couldn't stop her.

Nagisa damned himself to hell.

Korosensi had turned black, Nagisa could see. Hate literally radiated from the teacher. Nagisa felt intimidated. Yet he hoped with all his heart Korosensei could deliver the punishment Yanagisawa deserved. Nagisa gazed at Kayano once more. His eyes felt watery. She was his friend.

"Why…?" he asked. His legs felt limp again. He was so tired. He just couldn't focus on anything. Why was he like this? Why was he so useless? Nagisa fell to the ground, almost yelling a curse Korosensei would never approve of.

"You alright?" Karma asked, kneeling down and staring at Nagisa. He sounded… different. His voice was croaky. Nagisa couldn't blame him. Too much was happening for him to comprehend.

"I don't know." Nagisa answered honestly. He laughed. It didn't sound like laughter. It sounded like… wheezing. Nagisa pouted. He watched the battle for a bit. It was a mess of colour and sound. Nagisa wished he could focus properly. At least then he'd be able to see the battle properly.

"You look dizzy." Karma commented, his brow raised. Nagisa shook his head.

"What's going on?" he asked, rubbing his forehead.

Karma shrugged. His amber eyes widened ever so slightly. "I don't know. You just started acting all sick."

"That's strange." Nagisa commented. It was… unusual. Nagisa had never spontaneously got sick before. Was something wrong? Nagisa didn't know. He just felt so... horrible.

"Look." Karma said, pointing at Korosensei. Yanagisawa had been defeated.

"Oh, good." Nagisa commented. His head felt funny again. No, no, no, Nagisa pleaded his body, but it was too much. He blacked out.

"Yes, those types of dreams are purely tragic…" Nagisa heard Korosensei's voice. "But you know what is the worst? When you have a beautiful dream that feels so real, then you wake up and realise it was… well, just a dream."

"A dream?" Nagisa asked, shaking his head. He sat up. His body seemed to have regained some energy. Nagisa stretched his limbs. The grass was burnt. The sky was dark, yell full of coloruful lights. Destruction cluttered the ground. The classroom had been slightly damaged. Nagisa's classmates were surrounding him.

"You're awake!" Kayano exclaimed with joy.

"You're alive!" Nagisa proclaimed, staring at her.

"Korosensei saved me," Kayano replied. She frowned. A piece of hair was over one of her eyes. Nagisa clenched the grass in his fists. He felt… jumpy and strange. "But… then you passed out."

Sugino had a look of concern on his face. "We were really worried."

"Korosensei was telling us a lot about dreams, though," Kataoka commented, with a shrug. She folded her arms. "He also said you were… really underslept…"

"Underslept," Nagisa mumbled. He shook his head. "I guess I have been having trouble sleeping lately. What happened?"

"We defeated Yanagisawa, revived Kayano, and now…" Karma hesitated. Nagisa thought that was out of character.

"Children, this is the time we've been waiting for," Korosensei spoke up. Then Nagasi realized. "My assassination."

"No…" Nagisa mumbled. He shook his head. "No. We've been… waiting for this… but…" Something felt so wrong… in his heart, Nagisa felt he could do something, change something…

Nagisa felt he could save the Earth.

"Korosensei," Nagisa gazed at his teacher. "I know how to save the world. We don't have to kill you."

"What do you mean, Nagisa?" Korosensei asked. His smile was as big as ever. Nagisa remembered the drowsiness he felt. It was weird how he felt it before, but now it was gone. It felt unnatural too, like it wasn't meant to be there. Maybe he could apply the same logic to the assassination. Maybe Korosensei's assassination could be removed, just like his spontaneous drowsiness.

"I felt sick before, but I feel better now," Nagisa explained. "We can cure you, Korosensei. I know we can." His azure eyes glowed in the dark light. Everyone stared at Nagisa in interest.

"What do you mean by that?" Okuda asked, raising her brow.

"I mean…" Nagisa shook his head. "We can… remove the faults from Korosensei. We can make him non-explosive."

"I don't think that will work, Nagisa." Korosensei said, sounding a little upset.

"I'm trying it anyway." Nagisa said, wiping his brow. "I'll need needles! Someone, anyone..."

"Well, I've got this." Kayano handed him something that looked like a needle. "I used it when I was… injecting those tentacle genes into myself."

"Thanks," Nagisa said, accepting the needle. He walked over to Korosensei, his class eyeing him. He took a deep breath. "This dream is going to come true."

...

Cheers surrounded him. Nagisa smirked. He'd done it. He'd saved his teacher! He wrapped his arms around Korosensei's middle, tears in his eyes. The rest of the class joined in, all looking thrilled.

"Well done, Nagisa," Korosensei told him, patting Nagisa's head with his tentacle. "This indeed is a dream come true."

Nagisa couldn't explain his feelings of pure joy. He felt like a hero, a saviour. He cried out of pure joy. His friends were behind him. Nothing could ruin this moment.

Unless, of course, it was a dream.

Nagisa woke up. He looked around. He was in his normal bedroom in his normal house. Korosensei had been dead for seven years. Nagisa had never saved him.

But you know what is the worst? When you have a beautiful dream that feels so real, then you wake up and realise it was… well, just a dream.

Nagisa realised what was wrong. He was never drowsy during the real scene. It was only a dream. A nightmare - he felt ashamed that he couldn't help his friends. He let Kayano die. So his dream cruelly taunted him about it. Then it was his hope - his hope that he could save Korosensei, the best teacher he'd ever had.

But he couldn't. It was all just a dream.

Nagisa hated dreams.

He got up and went to his bathroom. He lived in a simple house in the city. He taught classes, just like Korosensei had. He was trying to be the best teacher he could. Or maybe that was a dream too.

Nagisa stared at himself in his bathroom's mirror. Tears were forming in his azure eyes.

"Dreams really are beautiful but cruel things…" he mumbled, bowing his head.