It all started one unassuming morning when Regulus poked his head around Sirius' doorway and hissed "head's up. Mum says Bella's coming to stay for the week."
Sirius' jaw dropped, as did his magazine "bollox" he muttered, hastily leaping from his bed and making for the window while Regulus disappeared into his own room. Sirius was grateful for the warning; he and Regulus hadn't exactly been getting along, not since the year before when Regulus had, predictably been sorted into Slytherin.
He had one leg out his window when the door banged open again. This time it was an even less welcome guest than his brother, Sirius had a feeling that awkwardness wouldn't be the only issue here.
His mother and Bellatrix stood framed in his doorway looking bizarrely out of place in his red and gold bedroom.
Bellatrix had her usual sneer plastered across her overly made up face while his mother looked ready to murder him.
"Get down from there" her voice rumbled dangerously "NOW!" Despite her outburst, Sirius didn't move, nor did he have the intention of moving; well not INTO the room at least. Sirius smiled slyly, not breaking eye contact from his mother for a second, then slipped further out of the window.
He was just about to make a break for it when Regulus' pale face appeared beneath his mother's elbow. He shook his head surreptitiously. Sirius sighed and swung his leg back over the windowsill, until both his legs were dangling where they hung from the ledge but still firmly inside. He and Regulus may have had their rough patches but he wasn't about to leave his brother to deal with those two trolls alone.
Sirius mustered up all his dignity and planted his feet firmly on the carpet with a dissatisfied sigh.
"Oh good, he's learnt how to take orders, like a good dog" Bellatrix laughed derisively and Sirius shot her a glare, his hands balled into fists.
"You're one to talk about dogs" he replied as smoothly as he could "you have a face like one."
A loud bang and a flash of purple light found Sirius face down on the floor, completely disconcerted, he half expected James to come through the door, chatting animatedly with Peter and Remus.
But as his eyes came into focus he saw nothing but a copious amount of black hair and Bellatrix's wicked, insane grin. "That will teach you not to cross me."
Still dazed, Sirius responded "I doubt it."
This marked the beginning of an increasingly awful week of hell for Sirius. He didn't know what he did in a past life to deserve this but knew he had to remain strong, even if he were so much younger than Bellatrix and could not use magic to defend himself.
To his credit Bellatrix was just as frustrated by Sirius' lack of fear as he was by her presence in the house. No matter what she did from torture to deprivation to good old fashioned knife attacks, the boy just would not break.
It was the night before she was to depart that Bellatrix gleaned any hope for inspiring fear in her cousin.
She was sitting at the table waiting impatiently for her breakfast to be served when a tawny owl swooped in through the chimney and made as if to fly further into the house… until Bella broke its wing. She walked leisurely over to the bird, plucked the letter from its leg and walked back to her seat without a second glance back.
The letter was obviously meant for Sirius but Bellatrix unfurled the parchment nonetheless.
'Sirius,' It read 'I got your letter and I want you to know that there's always a place for you with me and my family, even if you just want to get away for a little bit. I gotta say I'm worried about you so will you please try and stay out of trouble for once? And I know what you're going to say 'blah, blah hypocrite' but just do it. I chucked in a picture too, just for a laugh. Let me know how it's all going as soon as you can. James'.
Enclosed in the parchment was a picture of Sirius and another black haired boy Bella guessed to be James, both roaring with laughter at, what appeared to be, the giant squid tossing something that looked suspiciously like a small student up into the air before depositing him, slimy and dishevelled, on the grass.
Bella didn't see the fun in any of this but she certainly knew how to use the letter to her advantage. It was obvious, from the photograph and tone of the letter that Sirius must care very much for the boy who wrote it.
She was grinning obscenely when Sirius strolled into the Dining Room. He froze in place when he saw her and realised they would have to be alone together until he could get something to eat. He was on the verge of promptly leaving the room when Bellatrix began to read.
"'Sirius'" she started mockingly "'I read your letter and want you to know that there's always a place for you with me and my family' how sweet" she added sardonically. Sirius hadn't moved from his place since she started reading the letter but an obvious shudder ran down his spine when she read who it was from.
"What are you doing with my letter?" he croaked.
Bella laughed "finding your weakness" Sirius turned to face her furiously.
"You leave James alone." He spat hotly his hands curling and uncurling in frustration and fear.
"He even enclosed a picture" Bella cackled, holding it aloft, she watched his eyes follow its procession and knew she had him.
Bellatrix rose from her seat and paced very slowly over to Sirius. She stooped to his level and gazed earnestly into his eyes, still brandishing the picture.
"You've been very disrespectful towards me Sirius" she said as though she were a teacher telling off a misbehaving student "so, why don't you promise to be respectful to those who are better than you in the future, and vow you will do everything I tell you too as well. That should suffice."
Sirius' expression was stony, he bit back a retort and simply asked "or?"
Bellatrix smiled as if hoping he would ask "you've heard of the Imperius Curse, have you not?" Sirius nodded slowly, not liking where this was going "very good" she whispered "if you don't do exactly what I tell you to do, when I tell you to do it, I will put you under this curse and have you kill this boy, James, in the slowest, most terribly painful way that I can imagine… and I'll ensure that you remember every second of it."
Sirius felt bile lurch in his stomach and had to resist the urge to be violently sick over the hideous statement.
"Do you understand me?" Bellatrix asked sickeningly. Sirius' chest tightened painfully but he nodded once more "good" she said, still smiling, and with that she swept from the room.
Sirius didn't know how long he stood dumbstruck in the Dining Room but he did know one thing.
He had just figured out which family member he hated above all others.
Sirius never quite recovered from this particular threat from Bellatrix and spent over a year training to fight the Imperius Curse so this, his worst nightmare, could never happen in the future.
