Author's Notes: Written for the January 7th Prompt of the Day on Hogwarts Online II – "I love my sister, I don't care if you hate her or not, she's my family."
Narcissa was in a state of shock. She was numb as she lay in bed, the room seeming incredibly angry without Andromeda's deep, steady breathing. Narcissa shivered a little, pulling her covers tightly around herself like a cocoon. If she buried her face in her pillow and covered her ears, she could almost pretend Andromeda was still there in the other bed…
The sound of Bellatrix's voice startled Narcissa. She sat up in bed quickly, looking to the doorway where Bellatrix stood, framed in the light of the hallway.
"What?" Narcissa asked, her voice shaking and teary.
"Why are you crying?"
"I'm not." Narcissa shook her head, but when she raised her hand to her cheek, her fingers came away wet. She stared, slightly perplexed, but the second she saw the tears Narcissa felt her throat choke. Her face crumpled and she let out a short, involuntary sob.
"What is it?" Bellatrix asked, closing the door gently and kneeling on Narcissa's bed, gently wiping tears from her little sister's eyes. "What's wrong?"
"A– Andi!" Narcissa burst out, sniffling. "She's – le– left– and I – it's not fair!"
"Oh…" Bellatrix took Narcissa's hand in hers, stroking it. "I thought that was it. I know, Cissy. Andromeda…" She sighed. "You're right. It's not fair – believe me, I wish that she…" She broke off.
"Nothing," Bellatrix said quickly. "I just… I don't like that Andromeda left any more than you do. But," she added, "we can't let ourselves ruin our lives over her. She's gone, and we have to forget her."
"Forget her!" Narcissa's eyes went wide with horror at the very idea. "We can't forget her! She's our sister!"
"No, she's not," Bellatrix said. She suddenly sounded a lot less comforting – harsh, in fact. "That's why Mother and Father had her burned off the family tree, remember? Because she's not our sister anymore." Her face hardened. "I hate her. The stupid brat. How dare she…"
"Yes. I hate her. She's ruined everything! And you should hate her too!"
"I love my sister!" Narcissa hissed. "I don't care if you hate her or not, she's my family! And she's gone, and we'll never see her again –"
"You're being pathetic, Cissy!" Bellatrix's hand went up as though she was going to slap Narcissa. "She's not your family! She gave you up, don't you see that?"
Narcissa's lip trembled and she cringed away from her sister. "She didn't give me up!"
"Yes she did. She left you." Bellatrix's voice went soft, almost a purr. "Don't you see what happened, Cissy? Andromeda decided that she loved that Mudblood Ted more than you, and she abandoned you."
"How do you explain it, then? If she didn't abandon you, if she didn't give you up, then exactly what was she doing by running off with the Mudblood? Do you think she's planning to come back? Because she isn't…"
Narcissa had no answer to that. Tears threatened to spill from her large, pale eyes and she bit hard on her lip, trying not to cry. "I – It's – It's not true, she doesn't love him more, she loves me, she said so…"
"She lied, Cissy." Bellatrix's voice was soft and gentle – surprisingly so. She reached out and touched her little sister's cheek. "Andromeda doesn't love you. She never did. If she did, she wouldn't have picked that foul little Mudblood over you." She paused for a second, meeting her sister's eyes. "I do, though, Cissy, I love you… and I promise I won't ever leave you."