My attempt on a missing scene in the season 4 finale "The Feast of All Sinners" – I loved all the siblings' interaction and I understand they couldn't drag out their goodbyes for too long, but for me it was just not enough. Way not enough.

"Nick."
She was the only one to ever call him that, a nickname that reached back to the time when they were still merely humans, a life so different that very often he doubted it had ever been his.
Klaus closed his eyes for a moment, taking in everything the tiny syllable conveyed; all the frustration and anger that had carried them through the years, the vow that so often seemed more curse than the cause of the vow itself; the unanswered longing for salvation, for a sense. For a thousand years all they had had were themselves, and though they were more powerful than any other being they had never been enough. Never good enough.
Klaus turned around to look at the blonde standing in the door, very likely for the last time before the ritual. Before it ended.
"Rebekah." He had meant to sound sarcastic and uncaring, the way he used to, the way that always had angered her, but all that came out was a whisper, and it brought tears to his sister's eyes. Klaus made a step towards her but she shook her head, as proud as she had always and forever been. For a long moment they just looked at each other, watching their own helpless rage and love mirrored in the other.

Eventually, Rebekah brought on a bitter smile. "It's not fair. We'll do it", she quickly added as Klaus seemed to interject, "I'm not saying it's not the right thing to do. It is. But it's not fair."
Her look hardened as Klaus shrugged. "What? Do you think we deserve this? After all we've been through, after all you've been through to protect our family, to now tear us apart?"
Klaus didn't answer, and after a last glare the fire in Rebekah broke and she looked down.
"Never mind, I guess. Let's just get it over with." She looked up, and the pain shining through her eyes cut deeper into Klaus' heart than her hatred ever had.
This time she didn't stop him as he walked towards her and took her hands in his, trying to say something, anything, that could do justice to what his little sister meant to him. But he had never been good with words when they were not threats. He was a devil that boasted loudly and killed quietly, a bloody line through history, a red shadow. Elijah, too, had been a shadow, less bloody for the last centuries but still always lingering, searching quietly and desperately for a way to save what was left of their souls.
Klaus looked down on Rebekah's hands, her fingers intertwined with his.
"You are the light of our family", he murmured, "without you, without your endless struggle for beauty and love in life, I would long have… we both would have faded to even greater monsters than we are." He tried to laugh but his grip on Rebekah's hands became stronger. "You never gave up on this world, and on us. You never gave up hope."
Klaus turned away and closed his eyes against the only ache deeper than that of losing his siblings.
Hope.
He was losing hope, in every sense of the word. There would be no end to his missing her, no ease to his suffering. Always, and forever.

"She'll be alright." Rebekah's voice was dull, stubborn, convincing herself as much as him. "We'll be no part of her life but the rest of the world will be open to her, and the world's quite big."
"I know." Klaus shivered, each comfortingly meant word stabbing him. Rebekah was right. The world was big, and Hope would be able to make her way through it, to go wherever she wanted.
But he couldn't. He would have to make his way alone, to avoid every path that could lead him to the people he loved, to his family, his home. For decades he had tortured him, and they had stayed with him. Now that he finally was ready to show his love for them in a more civilised way, now that he was not afraid to be abandoned anymore – now he was losing them. Forever.

"Elijah told me you want him to leave you leave him should you ever drift off again." Rebekah sounded stronger now; some things were easier said when not looking in the other's eyes. He would know; he had spent hours talking to her when she was daggered. He had told her he was sorry, he had told her he loved her. He had hoped, then, that she didn't hear him say it, but that she knew it.
"Hey." The blonde reached for his shoulders and turned him around. "I get what you mean, but you're wrong. You are good now. As good as you have always been, except that now you're not afraid to show it." She smiled now. "You are what Elijah always saw in you, and better. You have changed your fate more than any of us. You will not fade away. You were a monster once, as were we all. But you are not a monster anymore. And I know you will never be one again." She bit her lips, tears shivering in her eyes. "You turned it all around with your love for Hope. I guess… after all the centuries of us trying to save you it's now you who saved us. Thank you."

He nodded, unable to speak at first, and they hugged.
"I love you."
Words far too weak to say everything that had to be said.
Rebekah leant deeper into the embrace. "I love you, too."
"Always…" Niklaus smiled.
"And forever."

She pulled back and held out her hand. "Are you ready?"
"To leave it all behind?" he murmured, looking across the room. New Orleans. Parties and massacres, fear and relief. The reunion of their siblings. Finn. Khol and Freya. That one crazy night with a hot werewolf girl that changed the world – and how he eventually had become part of this new world. Cami. Marcel. Elijah and Rebekah. Hope. Home.
"No." Rebekah shook her head. "To save my little niece."

"Let's go."