random fact: this story is planned to run, roughly, along canon, so pairings are now cemented as just the canon ones. Though I like the Harry/Draco relationship, so that will be a 'friendship'.
In any case, enjoy! Hopefully, updates on this will soon be coming quicker, as I'm near the end of my other fanfic.
Sorry if the writing style and characterizations are a little off in this one. Not getting anywhere near enough sleep at the moment, but oh well. Enjoy!

Amy Pond paced up and down Diagon Alley; she'd spoken to Ollivander, and found out about the seemingly pointless theft. Now, she was supposed to be heading back to Hogwarts, if Rory and his carriage ever arrived.

"Hey Amy!" his familiar voice called out.

He was coming down the cobbled stone streets in a large carriage, drawn by two, scaly, winged horse-like beings. Thestrals, if Amy remembered the books.

Her husband hopped off the carriage, before helping his wife up to the other side. "Back in a sec," he said quickly, "Doctor sent me to pick something up."

The redhead sighed, leaning back.

A minute or so passed, before Rory hastily ran back. He had a small bag from one of the shops in his hand.

Quickly, Rory got back up onto the carriage, throwing the bag down under the chair, before he started to guide the Thestrals on the journey back to Hogwarts.

"What'd you pick up?" Amy frowned, leaning forward tiredly

"Little black book," Rory smiled; "Doctor's told me to try and keep the timeline running as it should, or some techno-babble like that. Supposed to be Riddle's Diary."

O

Lellorian, proud centaur, galloped around Hogwarts castle. The boy would be here; it was certain. And sure enough, the black haired student wandered into sight, heading to his friend, the giant.

Lellorian knew the giant, too well. He'd attacked the giant once, knowing he would be of use. In the end however, Hagrid proved stronger. The centaur still smarted at the memory.

"Boy!" Lellorian boomed.

The child looked around, stepping back a little, surprised, as he saw the centaur.

The sallow creature galloped closer, moving with strong, confident leaps. He slowed, circling Harry a few times before stopping. Harshly, he glared from deep-set, darkened eyes.

"Will you obey me?" Lellorian demanded.

The black haired student tensed a little; of all things, he instantly remembered Malfoy's words. Though he harboured a distrust of the Slytherin, it seemed as if the blonde may well have been honest with his warning.

"Depends," Harry tried to hide the nervousness he felt.

"Yes or no!" Lellorian barked. Harry shrank back a little way, hands wandering to his wand.

"What do you want?" Harry gently slipped the wand out from his pocket.

"I want you to bring me something," Lellorian spoke in a deep, arrogant rumble, as if he couldn't so much as contemplate the fact someone would want to interrupt.

Momentarily, Harry scowled to himself. Malfoy hadn't been lying. The centaur wanted something; and no doubt, it was to be stolen, if Lellorian couldn't get it himself.

The student stepped back, slowly bringing his wand to his side. Quickly, Lellorian looked down, glimpsing the wand.

"Everte Statum!" Harry shouted, flicking a spell at the centaur. A ripple appeared to pass over the creature's chest; other than that, little happened.

Harry's eyes widened. He began to run, stumbling over the ground. Panting, the hex was discharged once again, from his wand: the centaur stumbled a little and, after a few steps, gave up the chase even though he could easily have caught up.

Harry groaned as he moved a little further away. Maybe he didn't have the time to visit Hagrid: which was a pain in itself, Hagrid was the person to talk to about insane centaurs.

Everte Statum was meant to knock foes away. Hermione had elaborated on it after a mention in Lockhart's class: and yet, when used on Lellorian, barely anything happened. Was it just because he was a centaur?

O

Flickering lights flashed around the interior of the TARDIS. The Doctor knelt in the centre, below the main floor, with the black book. A large, metal spire was rising off the pages; the source of the lights.

It was mostly dull, grey metal, covered with a chaotic mix of coloured wires and blue lights. Looking worryingly fragile, it ascended almost half a metre off the page, tapering to a needle-thin point at the top. Nearer to the bottom however, it covered most of one page, crossed the spine, and continued onto the other. Steam puffed out of the sides.

"Done!" the Doctor shouted, grinning to himself and falling backwards. He landed flat on his back. Quickly, he scrabbled back onto his knees, an instant before Amy ducked down into the chamber.

"Please tell me you're not serious," Amy rolled her eyes; "There's no way he's gonna miss that."
"Oh, alright," the Doctor made a face of childish disagreement, "Boring, aren't you?"

The Time Lord flicked a red switch on the side; almost instantly, the contraption vanished, leaving the book below, seemingly unaffected. Smiling, the Doctor picked the book up, shutting it and tossing it from hand to hand.

"What did you just do?" Amy blinked, a little surprised by the sudden vanishing of the machine

"Shuffled it along," the Doctor shrugged, "It's occupying a little space between the fourth and sixth dimensions."

"What about the fifth?" Amy frowned

"Oh, who needs the fifth? Nothing interesting ever happens in the fifth. Besides, ooh!" the Doctor jumped, "Pond! Pass the case."

"Yes sir," Amy muttered sarcastically, looking around.

Her eyes surveyed the area of the TARDIS console room around her. Either side, a mess of tools and equipment were thrown across the floor, only a small path leading to the Doctor's workspace was left clear.

Frowning, Amy knelt down, withdrawing the only case she could see; it was a mostly flat, plastic cuboid.

"Doctor?" She called

"Yes, that's the one!" he grinned

"This is a DVD." The redhead stated

"Yep," the Doctor grinned, "Well, a bit more advanced, but yeah."

"It's of Harry Potter and the Chamber of Secrets," Amy stated again, in the same tone.

The Doctor nodded: "What better way to fake an event? Get a recording of it happening already, think about it Pond."

Bemused, Amy threw the case over at the Doctor. He moved to catch it, and the case flew straight threw his hands.

"The fifth was definitely better at that," he mumbled, crawling over to pick up the case.

Speedily, semi-luckily, he continued with his task: buzzing the diary with his sonic screwdriver, making the device reappear, tossing the disc into a slot near the base, and flicking the device back into the strange dimensional limbo.

"There," he grinned, satisfied.

"Do I want to ask?" Amy sighed, resigned to the Doctor's customary oddness.

"Probably not," the Doctor hopped to his feet, "So, we get someone to memory charm Ginny, make her think she's been possessed, and then pass her this book. Which, by the way, has been rigged in an exceedingly clever, technical way-"

"It's steam powered," Amy interrupted, waving her hands through the air to get rid of a wafting puff of steam.

"Yeah, it is," the Doctor nodded, "Steam power is cool. Actually, no it's not. Unless you're in Starlight Express, which happens more often than you'd think… But steam engines don't have writing recognition kind-of-soft-ware, and don't play holograms of a movie." He grinned giddily. A moment later, he corrected himself: "Actually, yes they do. Sometimes. But mostly, no they don't."

O

Rory Pond wandered down through the fields, swamped in darkness. It wasn't night, and yet the sunlight felt as if it had been washed away: probably an enchantment. He was nearer to the Forbidden Forest than he thought he'd be, and indeed should be.

A small trail of spiders wandered past his feet. He looked down, frowning.

While he hadn't read the books to anywhere near the degree he should've (the books were still hopelessly lost somewhere in the TARDIS), it was common enough not to follow such a synchronized stream of arachnids into a place with 'Forbidden' in the name.

Still, the trail made him curious. Squinting, Rory peered through the trees. Deep in there, flashes were visible; orange, white and blue, in irregular, uncoordinated bursts.

Suddenly, the sound of footsteps, and twigs snapping, filled the air.

Inhaling, Rory backed away, running closer to the forest, turning a little, but not even breathing. The silhouette was moving towards the Forest.

Ok… It took him a few moments to think, and in reaction, he eventually decided to press himself to the rough bark of the tree, relying on darkness to hide him, as well as hoping the running shadow passed the other side of the trunk.

The noise continued, picking up in volume. Now he was quiet, he could focus on it; there was a sort of rhythm. It was more a gallop than normal steps, and yet it felt mildly irregular, as if unused to it.

A gust of wind brushed past him, carrying with it the smell of the woodland, as well as an unidentifiable stench. The creature had passed.

Still holding his breath, Rory looked sideways, catching a glimpse of whatever had run past him. He saw muscular legs, and matted, short brown fur covering a horse's body.

It was a centaur; one the Doctor and Dumbledore had both mentioned, quite possibly. Why would one ever leave the Forest?

Panting heavily, Rory made his way back to the castle. The flashes of bright white, blue and orange lights pulsed behind him, deep in the Forbidden Forest.

O

Harry Potter was bundled down the corridor, kept aloft by several spells. One arm lay limply at his side, unnaturally floppy.

A rogue bludger caused it: a Quidditch match, but only of the angry black balls had unremittingly chased after him, and him alone, By the end, he'd broken his arm.

And then Lockhart had insisted on 'helping', and by consequence, he was in a worse situation than he was to begin with. There was no bone in his arm; just floppy skin.

He was left in the Hospital Wing, after tasting some vile medicine intended to help him regrow his arm. Night quickly fell.

A hand gripping his shoulder soon awoke Harry. The black haired student fumbled for his glasses, finding them and, upon putting them back on, he looked up the pale hand which gripped his shoulder. He did not expect the face he saw.

"Malfoy?" Harry would have reacted somehow, if his arm wasn't so sore and useless.

"Shut it Potter," the Slytherin murmured curtly

"Come to gloat?" Harry muttered, facing up from the bed

"No. It's about Lellorian, if you'd actually let me speak."

"Huh?" Harry blinked, "The centaur?"

"Of course," Draco sneered, "You said no to him, right?"

"Of course." Harry echoed the Slytherin student's sentiment

"Knew it. He's gone back to talking to me; wants me to do his dirty work." Draco sounded repulsed by the idea.

Harry was a little surprised. He hadn't really seen much of Draco as a person; he'd mostly seen Malfoy the Slytherin, his public face. It was sometimes hard to remember that everyone else had their own lives.

"Why are you telling me?" Harry said, more mild-mannered this time

"A warning," Draco replied after a few seconds.

Harry inhaled; despite the fact his idea had just been illustrated. Malfoy, to his knowledge, wouldn't give any help to him at all, and yet apparently Draco had gone out of his way to warn him.

"Listen Potter," Draco muttered, "You know I hate you, but I hate Lellorian more. He's threatened Crabbe and Goyle. I don't really care, but you're Gryffindor, you like your friends a lot more. I don't think Lellorian's going to be upset if he has to hurt them."

With a cough, Harry shuddered.

So, the centaur was playing dirty; Harry fled, spewing curses, and now he'd returned and threatened Draco. Since Draco had seemingly refused, it was obvious Lellorian would speak to Harry again.

"Thanks Malfoy," Harry murmured grudgingly.

Draco sneered, not replying as he paced out of the Hospital Wing.

Slowly, the black haired Gryffindor exhaled, relaxing on the pillow. The inaction he was forced to take was a pain; for all he knew, Lellorian was preparing to threaten Ron and Hermione already. But he could do nothing.

Well, Harry reflected, maybe those new 'investigators', Rory, Amy and the Doctor, would do something about it.

He fell asleep, softly breathing.