Well, I did say that I don't follow story lines. I find them restricting. I base them loosely on the books and add twists.

Katja watched her Father fly off with the Order to collect Harry and Yasmin. Sarah came out, her hair neon blue. Sarah was a Metamorphmagus. Remus landed with Yasmin and Harry. The 4 went past. Sarah called through the door into the meeting
'Hello Snivellus!' Katja heard Sirius laugh.
'Detention Miss Black! Monday, 6 'o' clock, my office!' shouted Snape. The four climbed to their room. After a bit, Harry started shouting. The Weasley twins came and calmed everyone down. Soon, they were all aloud to come downstairs.
'Sarah what have you done to your hair?' asked Mrs Weasley. Sarah raised an eyebrow, neon blue to match her hair. All 6 pushed past and went downstairs, Sarah sliding down the banister. Katja, put a hand out to stop Sarah and pointed at Snape.
'Goodbye Snivellus!' Sarah called. Snape scowled and left.
'Sarah, don't do that.' said Mrs Weasley, sighing. Katja grinned. She admired Mrs Weasley's attempt to control Sarah, but she was fighting a battle she would eventually loose. They crept past the portrait, but a loud BANG made them look.
'Tonks!' said Mrs Weasley.
'I'm sorry! That troll leg!' cried Tonks, who was on the floor. Sarah put her hand to her forehead as Sirius's mum started to yell. She walked over and yelled
'SHUT THE BLOODY HELL UP!' Katja helped her mate shut the curtains. Sarah pushed her fringe out her eyes. They walked into the main room.
'Katja!' said Remus, looking up. Katja grinned as her dad gave her a hug.
'Hey! If she get's a hug, where's mine?' Sarah complained.
'Behind you.' said Sirius who had walked in behind them unnoticed. Sarah was lifted up into a giant hug, or so Katja thought. Sarah laughed and hugged her dad back. Everyone sat down.
''Fred-George-NO, JUST CARRY THEM!' shrieked Mrs Weasley. Everyone looked and dived away from the table. Fred and George had bewitched a large caldron of stew, an iron flagon of Butterbeer and a heavy wooden breadboard, complete with knife, to hurtle through the air towards them. The stew quickly skidded on the table to stop right at the end, leaving a long black burn on the wooden surface; the flagon of Butterbeer fell with a crash, spilling it's contents everywhere; the bread knife slipped off the board and landed, point down and quivering ominously, exactly where Sirius's right hand had been seconds before. Sarah looked up, and waved her right hand. The stew lifted itself and landed neatly in the middle, the black burn mark disappearing, the flagon of butterbeer landed on the table, and refilled and the bread knife landed neatly beside the bread.
'FOR HEAVENS SAKE!' screamed Mrs Weasley. 'THERE WAS NO NEED - I'VE HAD ENOUGH OF THIS - JUST BECAUSE YOU ARE ALOWED TO USE MAGIC NOW, YOU DON'T HAVE TO WHIP YOUR WANDS OUT FOR EVERY TINY LITTLE THING!'
'We were just trying to save a bit of time!' said Fred. 'Sorry, Sirius, mate - didn't meant to-' Harry, Sarah and Sirius were both laughing.
'Is it safe?' asked Yasmin, poking her head up. Katja was on the floor, Lupin had pushed her out the way and had his hand on the back of her neck.
'Boys.' said Mr Weasley 'Your mother's right, your supposed to show some sort of responsibility now you've come of age-'
'Supposed to.' whispered Sarah and All 3 girls lapsed into silent giggles.
'Sarah, what on earth have you done to your hair?' asked Sirius.
'Just noticed it?' asked Sarah, pretending to be shocked.
'No, this is the first chance I've had to ask you.' said Sirius. He ruffled Sarah's hair. She grinned.
***

Four girls sat on the train heading to Hogwarts.
'Wonder what will happen this year?' asked Sophie.
'Something. You know Fudge refuses to believe that You-Know-Who is back.' said Yasmin.
'Idiot.' said Sarah, sitting upside down on her seat, so her hair, which was a highlighter-purple colour and long, trailed on the floor, and her feet stuck up in the air. They emerged at the feast and Sarah stared at the apparently horseless-carrige. She patted the thin air.
'Sometimes I wish I couldn't see them.' she said.
'Oh so you can see them too?' asked a voice. They turned to see Luna.
'Yeah. Who did you see die?' asked Sarah.
'My mum. She was quite an extraordinary witch, but she did like to experiment, and one day, one of her spells went badly wrong. I was nine.' said Luna
'I'm sorry.' said Sarah.
'Yes, it was rather horrible. I still feel very sad about it sometimes. But I've still got Dad.' said Luna. Sarah looked at Katja.
'I know how that feels.' she said.
'Who did you see die?' asked Luna.
'Heaps of kids. Many died in the Orphanage.' said Sarah. They set off and walked into the hall.
'Who do you think that is?' asked Sarah. Katja looked to see a woman there, curly brown hair, a black bow perched on top. 'Ribbit.' croaked Sarah. The three girls laughed. After the feast, Umbridge made a speech.
'Drone Drone Drone.' said Yasmin.
'Ribbit.' said Sarah behind Katja and she turned to see an Umbridge clone behind her, much to the shocks of the first-years. Umbridge-Sarah grinned and turned back to normal.
'Well, as normal as Sarah get's' thought Katja.
***

Katja put her head on the desk. Her DADA were just going from bad to worse.
'Your previous instruction in this subject has been disturbingly uneven. But you will be pleased to know from now on, you will be following a carefully structured, Ministry-approved course of defensive magic. Yes?' she heard Umbridge say.
'There's nothing in here about using defensive spells.' said Hermione
'Using spells? Ha ha! Well I can't imagine why you would need to use spells in my classroom.' said Umbridge
'We're not gonna use magic?' asked Ron
You will be learning about defensive spells in a secure, risk-free way.' said Umbridge. Katja heard Sarah snort next to her.
'Well, what use is that? If we're gonna be attacked it won't be risk-free.' said Harry
'Students will raise their hands when they speak in my class.' said Umbridge. She paused.
'Rubbish.' said Sarah.
'It is the view of the Ministry that a theoretical knowledge will be sufficient to get you through your examinations, which after all, is what school is all about.' continued Umbridge, as if she had not heard Sarah.
'And how is theory supposed to prepare us for what's out there?' asked Harry loudly
'There is nothing out there, dear! Who do you imagine would want to attack children like yourself?' asked Umbridge
'I don't know, maybe, Lord Voldemort!' said Harry. Umbridge looked quiet frustrated, but when she spoke, it was in a voice that was calm.
'Let me make this quite plain. You have been told that a certain Dark Wizard is at large once again. This is a lie.'
'It's not a lie! I saw him. I fought him.' said Harry.
'Detention, Mr. Potter!' shouted Umbridge. Sarah stood up. Katja tugged at her sleeve.
'WOULD YOU ACCEPT THIS! He is back! If you don't, then we are all in danger! You ministry lot are being absolute idiots! Especially Fudge!' yelled Sarah.
'Detention Miss Black! All week! Now be quiet.' shouted Umbridge. Sarah was shaking, but she wouldn't sit down.
'I will not! I wil not shut up until you accept it! So put me in detention! I don't care!' shouted Sarah.
'Enough! You will be in detention for every night this term, starting tonight, and I will write to your father.' said Umbridge. Sarah sat down. When the bell went, Sarah shouted back in
'You miss, are a pathetic excuse for a teacher, who couldn't run a school even if it was full of nothing!' She stormed down to dinner, and Katja, knowing her mate all to well, knew not to follow her just yet.
***

Katja waited for Sarah to come back in from her Detention. She finally came in, tears down her face, clutching her hand. She didn't look at Katja, and walked straight past and up to her room. Next day, Katja glanced at her mates hand, and tried not to gasp. The words carved into her hand.
I Must Not Tell Lies
A letter dropped onto Sarah's plate, and she read it, Katja reading over her shoulder.

The letter was whisked out of sight as Sarah walked out, leaving most of her breakfast behind. Katja really felt for her mate.
__________________________________________________ ______________

Sarah walked down Hogsmead street, her hand hurting, staring at the ground, feeling like nobody understood her. She still had another 2 weeks to go of detentions, and was sure her hand would never heal. She looked up to see a familiar man with black shaggy hair at the Three Broomsticks, looking very concerned.
'Sarah. Come here.' said Sirius as he hugged his daughter. Sarah gave a weak smile. He let go and caught sight of her hand. She quickly hid it in her pocket, but Sirius gently took it out and had a look at it. He looked at Sarah's face.
'How long has this been going on for?' he asked quietly.
'Since you got that letter. I still have two weeks left.' said Sarah.