Author's Notes: Written for no heroes allowed's 48 Hours or Less Challenge on the HPFC forum.
Late one night, when Bellatrix was sitting in the parlour of Lestrange Manor, she was startled by a banging at the door.
Impatient with being disturbed, she took her time making her way to the front door, and by the time she arrived and opened it, the visitor was practically hysterical.
"Oh. It's you, Lucius. What're you doing here?"
"It's Narcissa. She's been out all night."
Bellatrix raised an eyebrow. "Your point?"
"Well– well–" he sputtered, "I'm worried about her!"
"Don't be. She's safe."
"She is?" Lucius's eyes widened. "So you know where she is? Where?"
"Here. Upstairs. With Rodolphus."
"What? What's she doing here with Rodolphus?"
Bellatrix stared at Lucius, then snorted, trying to hold back laughter. "Oh, take a wild guess, darling," she said, her face twisting into a derisive smirk. "Let me see… it's late at night, and a man and a woman are upstairs, alone…"
Lucius's eyes widened. "You don't mean…"
"Oh yes I do."
Lucius sputtered. "Well– you seem– very– nonchalant about it!"
"Obviously. Why wouldn't I be?"
"Oh, I don't know," cried Lucius, voice positively dripping in sarcasm. "Maybe… because Rodolphus is your husband! Doesn't it bother you that your husband and your sister are–"
"No, it doesn't. I don't care in the slightest what Rodolphus gets up to in his spare time. It's not as though I'd ever sleep with him."
Lucius shook his head, perplexed. "He's still your husband, though…"
"In name only," Bellatrix said. She smirked and took Lucius's hand, pulling him inside. "Come on… if it'll make you feel better, you and I can emulate Rodolphus and Narcissa…"