Luna hit solid ground sooner than she thought she would. Looking up, she saw they had only dropped a few metres and she seemed largely unhurt, along with Ginny and Neville.

"Reparo!" All three pointed their wands upwards, causing the hole they had crashed through to re-form itself, sealing them in, the sounds of the commotion above began to die away. Ginny helped Luna up, while Neville got to his feet. Now in complete darkness, Luna used wandlight to search around where their landing spot. It seemed to be along, narrow cave.

"Where are we?" Neville asked.

"Looks like one of the secret passages to Hogwarts," Ginny theorised, "Fred and George always said…" she stopped for a moment, remembering her brother again. Luna put a hand on her shoulder. "They always said they thought there were a few tunnels even they hadn't discovered." Luna and Neville picked up the unconscious Moonlight supporter, and they began head through the cave-like tunnel in a random direction, hoping it would indeed lead to the school. About five minutes later, just as Ginny was starting to think that the tunnel lead to nowhere, they spotted a spiral staircase in the distance. Luna and Neville carefully began to climb up, afraid the old structure could collapse at any moment.

"Ginny, hurry up!" Neville called to his friend, who seemed to be taking an interest in a corner of the tunnel by the staircase.

"Coming," she replied, hurrying at an alarming pace behind them. The staircase didn't last as long as they expected it would, and at the top, was a stone wall.

"A dead end," Neville said in frustration.

"Hang on," Luna said, darting in front of him, and leaning with force on the wall. As she had expected, it opened out onto another dark room, the small amount of light flooding the completely dark stairwell. She carefully stepped through the opening, and instantly recognised the other side as the dungeons of Hogwarts.

"We made it," she said happily. The three of them trudged along the corridor and out into the bottom of the Grand Staircase. Luna had to cover her eyes for a moment, as they adjusted to the strong light of the atrium.

"We better get him to Madame Pomfrey, before we do anything else," Neville stated, motioning to the figure he and Luna were still carrying. Growing weary, they carried on up the flights of moving stairs heading for the school's infirmary.

"Miss Weasley, Miss Lovegood," they turned to see the school's new headmistress, Professor McGonagall, marching towards them, "I was informed you would not be returning to school this year, and I certainly did not expect to see you here, Mr Longbottom."

"I'm sorry, Headmistress," Luna began, "We came here from Hogsmeade…"

"Hogsmeade?" McGonagall interrupted, "Then maybe you can tell me what on earth is going on over there, it sound like there's a full scale battle in progress."

"There is," Ginny simply said, "Professor, we have to get this man to Madame Pomfrey, then we can update you on everything."

"See that you do," the headmistress replied, walking off. Luna and Neville started moving again, grateful a few minutes later when they finally got to put the heavy assailant down. Madame Pomfrey was already rattling on about how to treat him, while Luna asked her to inform them as soon as he was conscious.

"We should make sure we have some veritaserum," Ginny suggested, as they left the infirmary. Luna nodded, it would probably be necessary. They took the trip to the headmistress' office, and begrudgingly had to re-tell the story of the last few days to her. She in turn told me of the miracle of no-one being killed after the derailment of the Hogwarts Express, and all other events of interests that had been happening in the school. She agreed to allow all three to stay in their respective houses for however long they would be here, and they decided to head there straight away, when they left the office, for some much needed rest.

As Luna walked in front of Neville and Ginny up the staircase, she noticed Ginny was reading a tattered-looking book. She had been reading it ever since they had arrived at the school. Having time to think again, Luna walked over beside her.

"What is it you're reading?"

"It's a diary." Neville looked nervous, recalling the last time Ginny had discovered a diary in the school.

"I found it in the passageway," Ginny explained, "Those are good places to hide things." She flipped the book back to its first page, and showed it to Luna.

"This diary is the property of Severus Snape."

"Snape's diary?" Luna said, interested. Ginny nodded.

"It's from when he was a student here. I've been reading a little bit of it. Did you know he used to have a thing for Harry's mum?"

At this point, Luna separated from her two companions, heading for her own Ravenclaw dormitories, while Ginny and Neville carried on towards Gryffindor. Luna felt a wave of happiness as she saw her house's common room for the first time in months, she was home again. Heading straight up to her own dormitory, she discovered to her satisfaction that her old bed was still free. She collapsed on to it exhausted, and feel asleep.

Luna spent the next few days trying to lead a normal Hogwarts existence, staying in her own house, and even going to a few classes. If this was her last time in the castle, she'd rather have these days as the last memories of her time at the school, instead of the horrors of her sixth year. Ginny seemed to be doing the same, and Neville had been helping out Professor Sprout with her Herbology classes, glad to be back in the familiar greenhouses. Luna possibly liked going to meals in the Great Hall most of all, tasting the house elves' food she always missed over the summer. She received an owl from Harry at breakfast one morning telling her of the Order's victory in the battle at Hogsmeade, and it was at dinner Ginny came over to the Ravenclaw table clutching the diary she had been reading for days.

"Are you still reading that?" Luna asked.

"Yeah," Ginny answered, "It's really interesting. Actually makes me feel a little sorry for how we treated him while he was a teacher here. But, the reason I came over was to show you this page I found, think you might find it interesting." Ginny put the book down in front of her, open at a page about half-way through, and went back to her own table. Luna began to read the entry.

"Well, today was another complete waste of time. Double Divination. I hate that class so much, and that stupid teacher, thinks she knows everything. Lily still isn't giving me the time of day, maybe I should just give up on her all together, probably blown any chances I ever had with her, and there are a few girls in Slytherin that I think might like me, although that crazy mudblood Naomi Ellis keeps giving me unwanted advances. At least I think that's what it is. She keeps pestering me about potions, wanting to know about Doxycide and Skele-Gro, why I have no idea, there's no connection between the two at all. She's completely demented…"

Luna looked up in shock. Snape had known her mother at school? She'd never heard about that. And why was she asking about Doxycide and Skele-Gro? Asking Ginny if she could keep the diary for a few days, to which she replied yes, Luna left the hall, heading back to her dormitory, to study it in more detail.

A day later, Luna had read a few more days in Snape's listings in the diary, when her mother was once again mentioned;

"Ellis bothering me again today, same potions. Why doesn't she just ask Slughorn if she so interested?"

Luna's head shot up. Of course, Professor Slughorn! She dashed out of the common room and hurried down the stairs towards the dungeons, losing five points from her house in the process. She hoped the potions teacher wouldn't have a class, she needed to find out about this right now. Her whole mission could depend on it. She reached the door of Slughorn's office, gasping for breath, and knocked sharply on it.

"Yes, how can I help you?" Slughorn asked politely as he opened the door. He was always uncharacteristically friendly for a Slytherin.

"Sorry to bother you, Professor," Luna said, "But there's something I really need to ask you some potions."

"Of course, come in, come in," Slughorn replied, stepping back into the office. Luna followed, noticing how much brighter the office looked than when it had been Snape's domain.

"I wanted to know something about my mother," Luna explained, "Naomi Ellis."

"Merlin's beard!" Slughorn cried in surprise, "Naomi Ellis was you mother?...I remember her, brilliant student, fantastic at potions. Tell me, what is she doing these days? I always saw her working in potions after she left."

"She's dead," Luna explained, "Died when I was nine." Slughorn looked saddened.

"Oh, I'm sorry to hear that, shame, terrible shame. What was it exactly you wanted to know?"

"Do you remember her ever coming to you asking about Doxycide and Skele-Gro?" Slughorn looked deep in thought for a moment.

"Yes, yes I do," he said, "I must say I was surprised, neither of those potions are contacted, and they're everyday concoctions, but your mother seemed to think there was something you could do with both of them."

"Is there anything you could do using both of them?" Luna asked, "And maybe using three other potions?" Slughorn looked thoughtful again for a moment, longer this time.

"There is a legend I vaguely remember," Slughorn explained, "Just a silly myth though, like Crumple-Horned Snorkacks," Luna stopped herself from saying anything, "It did say though, that if you put five potions together, I'm sure Doxycide and Skele-Gro were involved, and fired a certain incantation at these potions, it could give you ultimate control over magic."

"Ultimate control?" Luna enquired.

"Yes. It would give whoever cast the incantation an unlimited source of power. They wouldn't even require a wand, and could do almost anything they wanted, like kill someone a thousand miles away without even needing to move, for example Someone like this would be, in theory, invincible." Luna was getting worried.

"Of course," Slughorn continued, "The whole thing's just a myth." Even he looked concerned about what he'd just said.

"Do you remember what the other three potions are?" Luna asked.

"I'm afraid not," Slughorn told her, "It was years ago I heard about it, I can only remember a few details unfortunately."

"Do you know anywhere I could get more information about it?"

"I can't think of anything in particular, but if you check the library for books that mention Doxycide and Skele-Gro, there may be a mention in there."

"Thank you, Professor, you have been most helpful."

"Think nothing of it," Slughorn replied, looking at Luna. "You know, I can't believe I never saw it before, you're the spitting image of her." Luna smiled as she went back out of the office into the dim dungeon corridor.

That afternoon, Luna, Ginny and Neville were sitting in the library, a stack of books in front of them on the table. All three looked bored and exhausted as they painstakingly looked through each of the books they knew contained a reference to the two potions.

"This is hopeless," Ginny broke the silence that had lasted for hours, "All of these books just say exactly the same thing. Doxycide renders Doxies unconscious and Skele-Gro grows back bones, just the standard stuff, nothing about any power-giving machine thing." Luna and Neville seemed to agree, putting down there own books, Luna rising from her seat.

"I'm going to go feed the Threstrals, I think," she stated, "Haven't seem them since I got back."

"Can I come with you?" Neville asked, "Unless you want to be alone."

"No, that's okay" Luna told him, "I wouldn't mind some company." After fetching some apples from the kitchen, the two teenagers strolled down to the Forbidden Forrest where the large black creatures were waiting, as if knowing Luna would be coming to see them today. They fed them in a calm silence.

"We're getting nowhere," Luna stated suddenly.

"Don't give up," Neville urged her, "We'll find what the other three potions are, somehow. I have faith in you."

"Thank you, Neville," Luna smiled at him, "I just wish I knew why my mother wanted to build that machine. I knew her, she would never want that kind of power."

"Well," said Neville, pulling a small stone out of his pocket, "We could always ask her."