Disclaimer: Unfortunately, the only things in this whole story are my main character, Tara, and the plot. JKR owns the rest.

Author's Note: Alright. It seems I finally managed to catch an elusive plot bunny and write about it. I have so many ideas written down and this is the only one that seems to really work for me. I am sorry for the long delay between stories. Call it a hiatus, if you will.

Power The Dark Lord Knows Not

Chapter One

Hermione Granger was rushing through Diagon Alley. She was late to make it to the Weasley'sfor dinner.

In her great rush, she bumped into someone. A hand shot out and caught her arm with quidditch-like reflexes and prevented her from landing in a mud puddle.

Hermione looked up into a pair of sparkling emerald eyes that seemed to be laughing at her. She could not help but sheepishly smile back. The girl looking at her was tall and slender with straw blonde hair and a mouth that was drawn up in a friendly smile. The smile encouraged Hermione to continue to smile.

"Hi. I'm Tara. Nice to meet you, although the circumstances are regrettable," said this new, pretty woman.

Hermione's smile became wry. "I was not paying attention. I am at least as much to blame as you are. I am Hermione." Tara's eyebrow rose and her eyes sparkled as her smile widened. Hermione grinned in response. "I am rather hard to miss, aren't I?" she asked, referring to her large bushy hair and the extensive media coverage that she received as one of Harry Potter's best friends. Tara merely smiled in response.

Suddenly a voice, cold, hard, and familiar, interrupted. "Aww. Did the filthy little Mudblood find a friend?" the voice sneered.

If it had been up to Hermione, the two girls would have walked past the blonde boy with nothing more than a 'shut up, ferret'. However, that choice was taken out of her hands.

"Have we met?" Tara's voice came out soft and cold. It reminded Hermione of someone but she could not place who exactly.

Now that Tara was turned around and the boy could see her face, his eyes lit up. She was very pretty, after all. "I don't believe I have had that pleasure, no." He offered his hand. "I am Dr-"

"Malfoy," Tara cut him off. "And you seem to be as much of a prat as your father."

Hermione and Malfoy both did a double take. "You know my father?" he asked curiously.

Tara's cool mask transformed into an incredulous stare. "Is there anyone who does not?" she asked dryly.

Malfoy studied her, his brow furrowed as he pondered her. The attitude was familiar,

But from where? He suddenly stifled his curiosity and sneered, "You're one of Father's mistresses, aren't you?"

Hermione gasped but Tara just said coldly, "Oh, yes. I am certain that your dear old dad would be so proud of you right now."

It looked as if Malfoy might physically attack them. Hermione's hand began to inch towards her wand but Tara reached for her wrist and led her away. Hermione glanced over her shoulder at Malfoy, who was looking directly at them but seemed confused.

"He can't see you," Tara said easily.

"Why not? I can see him." Hermione looked legitimately confused.

"I can make myself impossible to see and I made you invisible as well when I grabbed your wrist."

Hermione stared. "Like a Disillusionment charm?"

Tara smiled. "Not quite. It's just something that I can do."

The other girl stared in awe. She had, in all of her years reading, never heard of anything like this.

"You know what?" Hermione asked. When Tara looked at her, she continued. "I am going out to see some friends for dinner. Would you like to come along?"

Tara began to grin. "If no one will mind. I don't want to impose on anyone."

"You won't be imposing on anyone. Here," she said, offering her hand. "I will Apparate us there."

"Where is 'there'?" Tara asked as she placed her hand in Hermione's.

There was the experience of being squeezed through a tube much smaller than she was, and then she was standing in front of a fairly small, run-down house. There were trees running along the fence line so that she could not see the rear yard. She could, however, hear the talking and laughter from behind the trees. She turned to Hermione and waited for the answer to her question.

"Welcome to the Burrow," Hermione said with warmth evident in her voice.

Tara smiled. "I think it's brilliant," she said, unknowingly quoting Harry Potter the first time he had seen the house.

Hermione led her through the house and out to the backyard. The place was crawling with redheads! There were eight of them when she counted. There was also a man with sandy brown hair and many scars standing with a woman with blinding pink hair. A tall, very familiar old man was standing with a tall pale man with long, dark, greasy hair who was glaring at Hermione for no apparent reason. Harry Potter was also standing off to one side with one of the redheads.

The place really was brilliant! Hermione dragged Tara over to an older woman with bright red hair. "Mrs. Weasley? This is Tara."

Molly Weasley turned to look at the two girls and smiled. She pulled Hermione into a hug, moaned about how thin and peaky she was and then turned to Tara.

Molly smiled widely at her and pulled her into a hug just as she had done with Hermione. "Hello, dear. I am Molly Weasley, Ron's mother."

Tara smiled and resisted the urge to snuggle into the woman's warm embrace. It was so rare that she was hugged. "I'm Tara," she said softly.

Molly pulled back and smiled warmly before calling out to the rest of the group. "Everyone, this is Tara. She is a friend of Hermione's."

Everyone called out a greeting except for the old man (who was looking at her strangely) and his companion. She looked at them and smiled as she headed towards them.

"Professor Dumbledore," she greeted quietly.

The old man smiled. "You look different," he said just as quietly.

Her smile immediately died. "It was necessary." Before Dumbledore could say anything more, another redhead burst through the back door.

"Percy!" Molly called out eagerly. Being as Percy worked full time at the ministry of Magic and was rather a workaholic, his family did not see him very often.

It was Bill Weasley who noticed his brother's pale face and wide hazel eyes. His glasses sat crookedly on his nose and his usually impeccable hair was rumpled and unkempt. "What's up, Percy?" he asked, both curious and concerned.

Percy appeared to be hyperventilating, Tara noted calmly. She was reasonably certain that she already knew what his crisis was.

Finally he managed to wheeze out, "The MacDonalds are dead."

There was a collective gasp from everyone present except Tara. The first person to speak was Harry. "Who are the MacDonalds?"

It was Arthur Weasley who answered. "They are an old wizarding family - older than the Malfoys. Back in the days of the Hogwarts founders, there was royalty in the wizarding world. The MacDonalds were the royal family. They continued to rule until the people decided that they wanted a democracy. That was when the Ministry was formed. The only MacDonalds left were an older man, his wife, and their daughter."

Percy had sufficiently recovered himself and announced, "The man and his wife are dead. Aurors did not find the body of their daughter. It is believed that she was taken by Death Eaters."

Dumbledore, who had previously remained silent, calmly stated, "I have my doubts."

Before anyone could question this odd statement, the young woman with the pink hair burst out, "But now Harry will not have their help!"

Tara's gaze swivelled over to the young woman who had spoken and then to Harry Potter himself. He had gone very pale. "You mean that I had help and now they are all dead?"

Before Tara could speak, Dumbledore said calmly, "Exceptfor the daughter."

"Who was captured by Death Eaters," Harry finished angrily.

"I wouldn't count on that, actually," said a cool female voice.

Everyone turned to see a tall slender girl with long black hair and piercing grey eyes. Dumbledore was the first to address the stranger. "Ah, Miss MacDonald. I had hoped you would find me."

Hermione turned to look for Tara, wondering what she thought of this new development. Her companion with the blonde hair and laughing green eyes was gone. "Tara?" Hermione called, looking for her.

"Yes," a familiar voice asked. Hermione turned to the source of the voice and saw this 'Miss MacDonald' looking at her with a familiar smile.

"Tara?" Hermione asked again, this time filled with awe.

The MacDonald girl held out her hand to Hermione. "Hi. I'm Tara… MacDonald," she said, quoting her earlier introduction but adding her last name.

Everyone gaped except, of course, Dumbledore, who smiled and said, "It has been a while, Miss MacDonald. Are you quite alright?"

Tara had a brief memory of her parents begging for their lives while she remained unseen in the corner. She quickly pushed the memory aside. "I will be fine. How is Minerva?" she asked, shocking everyone present yet again.

Suddenly Tara laughed, feeling someone attempting to prod her mind. She turned to the man with Dumbledore. "Professor Snape," she said cheerfully.

Severus Snape was staring at her. She may as well have not been standing there for all the good his Legilimencydid for him. He did not even come up with the slamming into a wall sensation he got when he came across someone using Occlumency. On the other hand, she seemed to have broken through his Occlumency (which was rather strong if he did say so himself, which he did) and known who he was and what he was doing. This girl was certainly… different.

Dumbledore laughed as well. Soon the party was back in motion and Percy agreed to stay. His tension and the glances Tara continued to receive were the only indication of the earlier fiasco. Tara remained with Dumbledore and Snape.

"You never did tell me how Minerva is doing."

Albus Dumbledore smiled warmly. "She is doing well, Miss MacDonald. She is worried, of course, about Mr. Potter."

"Aren't we all?" Tara asked. She then turned to Snape. "We know you are worried even if you do not like him."

Severus blinked. The girl was uncanny.

He turned to Albus, deciding to ignore the girl. She smirked but he did not notice. "Have you found me an assistant, Headmaster?"

"Severus, there is no one willing to take that kind of a risk," Dumbledore said with a sigh.

"What do you teach, Professor?" Tara asked innocently.

"Potions," Snape bit out.

Dumbledore's eyes took on an ominous twinkle. "Severus, I have thought of someone. I still have to ask them, however."

Snape looked suspicious but nodded. "I need a drink," he muttered as he stalked away, his robes billowing out behind him.

Albus promptly turned to Tara and she smiled. He smiled widely in return. "What do you recall me telling your father about the Order of the Phoenix?"

Neither mentioned that her remembering anything was against the rules.

"I believe," she began, "that it was a secret society that fights Voldemort and his followers."

"Indeed," Dumbledore agreed. "As such, we have a spy within the Death Eater ranks-"

"Professor Snape," she cut in.

Dumbledore nodded, not at all fazed by her knowledge of this top secret fact. "Yes. He has lately been called away often and requires some assistance in the management of his classroom and paperwork."

"And you want me to do it," Tara finished. At Dumbledore's nod, she asked, "Would he not be required to kill me? After what happened to my parents…"

Snape's voice answered her. "They wanted you alive."

Tara's eyes widened. "Why?"

Snape narrowed his eyes at her. "Your abilities," he replied bluntly.

She pondered this for a moment. Finally she said, "So I could spy as well."

Dumbledore shook his head. "I don't think that is a good idea." At her questioning look, he explained, "They only wanted you for what you can do. You would be forced to kill many people and then tell me all of the details. That or you could refuse to kill innocent people and be killed."

Tara snorted. "He can't kill me if he can't find me. Besides, how is that any different than what the professor does?" she demanded, pointing at Snape.

"You foolish girl," Snape snapped. "I have no reason to live! If I fail, it is no great loss."

Tara's eyes flashed. "And what have I got to lose? My parents are dead and I have no friends other than Professor Dumbledore."

Molly Weasley chose that moment to appear. "Dinner is on the table, dears." The three of them nodded absently and she walked away, wondering what was going on.

After Molly was gone, the silence continued. Finally Tara said, "I will be Professor Snape's assistant on the condition that after two months I will be able to decide for myself what I want to do. At that point, I get to choose. I will leave you to discuss it."

As soon as she had walked away, Snape turned to the headmaster. "Absolutely not," he said resolutely.

Dumbledore was watching Tara with his head tilted to one side as if he heard something. Snape heard nothing. Albus eventually turned to the Potions Master. "Severus, we don't have much choice. If we say no, she will disappear and Harry will be on his own, not to mention that you will still have no assistant."

Severus burst out, "But if we say yes, she will get herself killed and then she will be no use to either myself or Potter anyways." He sighed. If it had been anyone else as young as she was, he would have said no with thought of protecting them. As it was, she may be the only hope they had to help Potter defeat the Dark Lord.

"I don't suppose I need to remind you what the Dark Lord will do with her."

Albus sighed again. "No, Severus, you don't. I don't like it either. You know how much I hate sending you to him. It would be so much worse with her."

Severus arched an eyebrow. "How so?" he asked, feeling nearly envious of the girl before he stifled it.

Dumbledore smiled sadly. "I very nearly raised her. I tutored her in the evenings for years. After she had frightened off all of the available tutors, her father sent me an owl. He wanted to know if I knew of any more.I met her and decided that I had to do it myself."

"I'm sure her father was thrilled," Severus muttered darkly.

Albus chuckled. "Something like that."

Severus returned to the topic at hand. "She's too young to be spying and she has no training."

"You were young with no training."

"Yes," Severus agreed dryly. "And my sunny personality is a stunning goal for her to strive for."

Albus chuckled again before becoming serious. "Honestly, Severus, we have little choice."

Severus sighed. "I know. I just don't want her to suffer as I do."

"I appreciate the thought, Professor." Her voice came from behind him.

Dumbledore smiled widely at the scowl on Snape's face. "We want you as an assistant."

She smirked, her grey eyes sparkling mischievously. "I know, Professor."

"If we are to work together, I insist that you call me Albus."

Tara smiled warmly. "Yes, Prof- Albus."

Snape was sizing her up and she could feel it but she ignored it and told the professors that Molly had saved them some dinner. Albus smiled and headed wordlessly towards Molly.

Snape stayed behind and continued to study Tara. She was watching Dumbledore walk away and ignoring him entirely. Finally, he felt the need to speak. "I imagine you will be living at the school with the rest of the staff?"

"That is the idea," she said, finally turning to look at him. "After all, where else am I going to go?"

Severus had to admit (only to himself, of course) that he had not thought of that. "When will you be arriving?"

She smiled. "When do you want me to be there?"

He scowled. He didn't want her to be there at all. "The rest of the teachers will arrive a week or two before classes start."

Tara studied him for a long moment. "I know you hate the idea of my doing this, Professor, but what else am I supposed to do? I have nowhere to live, I can't use my Gringotts account, as I can be traced through it.I have no income, and I have a bunch of Death Eaters after me. I am sorry that it bothers you, though."

"You're just so young," he muttered.

Tara gave an unladylike snort. "Just how young do you think I am, Professor?"

Feeling as if he had missed something, Snape made his best guess. "Eighteen or so."

His new assistant threw back her head and laughed. "I am flattered, sir."

Snape felt his eyebrows rise. "How old are you, then?" he demanded.

"Twenty-five," she replied cheerfully.

He could not help but look her over. She looked no more than a day over twenty.

Albus chose that moment to stroll out of the Burrow with Harry Potter at his side. "Harry, this is Miss MacDonald. She will be assisting Professor Snape this year."

Harry Potter, the Boy Who Lived, held out a hand to Tara, who took it and smiled. "You must not come and hesitate to come and visit me once the term starts.I have a feeling that we are going to need one another."

She heard Snape mutter, "More like he will need you, the incompetent fool."

It seemed that Harry had heard him as well, as he flushed and his green eyes flashed dangerously. Tara caught his eye and Snape watched in interest as Harry's eyes widened and shot over to her. She merely smiled at Snape when he looked at her.

Finally Harry grinned at her. "I'll come and visit all the time. Do you mind if I bring Ron and Hermione along?"

Tara smiled. "Of course not. They are part of this mess, too."

"Harry!" Molly's voice carried from the kitchen.

He grinned apologetically. "I have to go. When the term starts, I will come and see you."

Tara just smiled and nodded before he took off at a jog when Molly called for him again.

"Dunderhead," Snape growled.

"Maybe," she admitted. "But he's a nice dunderhead and the fate of the world rests on his shoulders."

Snape sighed. "So everyone keeps telling me. If you tell me to take it easy on him, I will beat you about the ears."

Tara laughed. "I'll be sure to make a mental note of that."

Albus had to smile as, at her comment, Severus' eyes took on a new sparkle and his mouth began to twitch in a manner that was suspiciously reminiscent of a smile. It seemed that Hogwarts' newest employee was having a good effect on their resident spy. Dumbledore could not have been more pleased with the way things were turning out.

However, night had fallen and Tara looked dead on her feet. She was no good to anyone when she was nearly dead. And so, with that, Albus sent them all to bed.