It was remarkably easy for Harry and Tonks to sneak into the department of mysteries. When they had arrived in the atrium the alarms were still going off, the guard on duty waved Tonks through the new barrier as soon as she waved her badge swiftly and seemed to be more focused on the bells than Tonks. As she was about to go through the barrier she paused and asked the guard "Wotcher, I don't suppose you know what's up with all these bells?" As she talked she felt Harry slip past her, hidden under his cloak.
The guard shook his head and gruntened in what she took as a negative. After it was discovered that Harry and his friends had basically just walked straight into the ministry earlier that year the defenses of the ministry had improved. Now every employee had a badge that they had to show to the guard, that guard would then open a barrier similar to the one at nine and three quarters.
Without the guard opening the barrier there was no way to get to the elevators, but whenever someone walked through the barrier it stripped away all disguises. It seemed the only exception was Tonks' metamorphmagus powers and hopefully Harry's cloak. The hitwizards on guard around the barrier were constantly on alert and Hermione had assumed would notice the feet of someone under an invisibility cloak, meaning that only one person could join Tonks with the break in.
The elevators themselves weren't under as much scrutiny so nobody noticed when Tonks stepped into an empty elevator and tapped her auror badge where the button for 'level nine' used to be. Once the elevator had begun its descent she used her power to make herself smaller and joined Harry under the cloak, by the time the elevator had reached its destination they were both carefully hidden under the cloak.
Together they left the elevator but Tonks held her arm out to stop the grates shutting while Harry looked at his watch and whispered "The time is… 7:33 pm… 34… 35 Okay let's move on" they kept walking even when they heard the elevator doors close and go back up to the atrium.
The door into the department would normally have been locked under the best enchantments the unspeakables knew, it had taken Lucius Malfoy almost an entire year to finally figure out a way through even with help from imperioused unspeakables, it would have taken Harry and Tonks far longer… Fortunately when they reached the door it was wide open with two unspeakables standing guard on either side. One of the guards had started down the corridor to investigate the elevator so there was enough room for the two of them to squeeze past the remaining guard.
The spinning room would have held them up but with the front door held open the rooms protections couldn't activate. "Time room" Harry whispered, hoping they hadn't changed how the room worked since his fifth year.
As he had hoped a door opened and golden light trickled into the room, the two unspeakables on guard noticed the change in light and rushed into the room, letting the door shut behind them, by then Harry and Tonks had hurried into the time room and forced their own door shut. They had no way to tell for sure but Harry hoped the unspeakables would take a moment to find them since the spinning room would have covered their path.
The room was almost completely unchanged, most importantly the time turners were still in the same constant loop of crashing and repairing. He took a moment to familiarise himself with the loop before he focused on a single time turner that fell slightly slower than the others and said "Accio Time turner" just as it finished its repair loop. It flew into his hand just as its brethren broke once more.
Harry threw the chain over their necks just as the door flew open to reveal another two unspeakables, Tonks threw a blasting curse at the remaining time turners while Harry span the time turner just one rotation. Everything in the room started going in reverse but not before they saw Tonks' curse reduce the remaining time turners into fine dust.
Once time had stabilized the two took a moment to breathe and welcomed the temporary silence from the alarms, then they hid by the door to the spinning room and Harry cast a basic unlocking spell at it. As expected the door didn't open and the alarms began to ring, immediately the door flew open and unspeakables flooded into the room, before the door could close behind them Harry and Tonks crept into the spinning room.
When they had entered the time room Harry had noticed the time room was 4 doors clockwise of the front door, so just before the time room closed Harry fired the same fire marker Hermione had used at the door 4 along clockwise. When the spinning ended they opened the door marked with the dot and sighed in relief when they saw the elevators.
Looking at his watch he saw they still had most of the hour left until their past selves arrived with the elevator. They couldn't call the elevator from the department as every unspeakable would be notified and they would rush to the elevators before it could arrive.
If they hadn't set off the alarms then their past selves would have never been able to activate the elevator without alerting someone and preventing them from getting into the department in the first place. If they hadn't blown up the time turners then a future unspeakable would have arrived and warned the past unspeakables about what was going to happen.
The two sat in a shadowy corner and prayed the unspeakables didn't have a way to detect or see through Harry's invisibility cloak, if he wasn't so nervous Harry would've found it funny to see the unspeakables run up and down the corridor trying to find out where the intruders had gone.
Eventually much to Harry's relief the elevator arrived and the two crept past their past selves and into the elevator. Once the guard had gotten far enough away from his partner Tonks pressed the button for the atrium, getting out was much easier since despite the new security the wizards lack of common sense meant nobody checked who was leaving so she morphed herself into one of her coworkers and went through the barrier. The moment she was out of the anti-apparition wards she felt Harry grab her and he apperated them back to shell cottage.
The unspeakables never did learn who broke into their department or why the only thing taken was a single time turner, a few days after the news broke about the Dark Lord's death they had found a letter in the time room "Sorry I took this without asking, needed it to stop Voldemort, cheers". Enclosed was the remains of a charred and broken time turner, only a few grains of pixie dust remained stuck to the glass and what was left of the golden frame was heavily dented.
Many years later whenever a new unspeakable got given a tour they would be shown what was once the time room as a warning of what could happen. Where the time turners used to sit there was now a miniature tornado of pixie and gold dust, people had lost their minds looking too deeply into the sands as every now and then words or images would appear within the sands. Those messages would then be dutifully written down and stored within the halls of prophecy, without fail each and every message would be proven correct with time.
The only other object within the time room was a large hourglass which had once held an egg, now it held a broken time turner that would rise and fall. At its peak it resembled a freshly made turner, at its lowest it became a collection of golden dust. But when it reached the midway point it once more became the broken time turner that had become the symbol for the defeat of evil.
Whenever a new Dark Lord arose the time turner would freeze in either the top or bottom half of the hourglass. If the time turner stopped in the top half then the unspeakables knew this dark lord would fall before achieving anything. But if the time turner stopped in the bottom half then they knew dark times were ahead, as if in response to the broken time turner in the hourglass the tornado of sand would speed up or slow down.
If the tornado grew too slow then the bells of the department would ring again and the unspeakables would discover that the last time turner had disappeared, the morning after they would find the time turner returned and the sands of time spinning again, they would then receive the news that the latest Dark Lord was dead. The unspeakables suspected that if the sands of time stopped completely then all hope was gone and life as they had known it was over.
Harry waited outside Shell cottage anxiously, when they arrived back they had hidden the time turner behind Dobby's grave. An hour later Ron, Hermione and Griphook had then used that time turner to go back and meet them, currently the past versions of themselves were coming up with the very plan they were carrying out. Hermione was currently helping Tonks perfect her disguise, Hermione had used the Polyjuice potion to turn into Bellatrix so that Tonks could then use her as a template.
They had planned to use the Polyjuice to sneak into Gringotts but Tonks had warned them about the thief's downfall, which meant they needed to have a disguise which couldn't be stripped away which as they had discovered at the ministry meant Harry's cloak and Tonks metamorphing ability.
In order to distract themselves from their nerves Harry and Ron were going over their strategy again. Eventually the girls appeared, both looked identical and Harry found it impossible to guess which of them was Hermione.
"Wotcher, we have hit a bit of a snag… I can't get my voice to mimic Bellatrix's"
"We tried everything Harry but it would take hours for her to get the voice perfect and even with the time turner we don't have that sort of time."
Harry groaned quietly and started thinking "It's fine… I'll just have to do the talking, which wouldn't be out of character for him anyway."
They waited for Tonks to transfigure Harry's face into Voldemort's, as a metamorphmagus she knew more about human transfiguration than the other three combined and by the time she finished Harry looked almost exactly like Voldemort, it was fortunate Harry had grown so much over the year as they hoped he was now almost as tall as Voldemort.
Harry threw the chain around the five of them and spun the turner twice, the moment everything stopped reversing Ron and Hermione disillusioned themselves and Griphook and then hid under the cloak together. The cloak would stop anyone easily detecting them while the disillusion charm stopped their feet or hands being seen.
Griphook climbed onto Harry's shoulders since he wouldn't be detected by Gringotts security and they hoped the sight of Voldemort would stop people looking too closely at anything above him, once all that was done Harry put his hand on Tonks shoulder and felt Ron and Hermione put their hands on his shoulder.
Together they apperated to Diagon Alley where Harry immediately began marching up to Gringotts, Tonks following slightly behind him. To an observer it looked like she was timidly following him and letting him take command but in reality she was on the lookout in case someone got too close and tried to attack Harry while he was disguised as Voldemort.
Harry barely glanced at the witches and wizards huddled in the shadows, normally he would have tried to help but he knew the only way he could help them today was to act like Voldemort and he would never try and offer help.
It didn't surprise Harry when a young man charged at him, as they had rehearsed he waved his hand towards the man, just before Ron and Hermione hit the man with a paralyzing and knockback jinx. Both jinxs were invisible and left no obvious trace, which played to the illusion that he was using wandless magic.
When they reached the doors to Gringotts Harry noted that the goblins looked ready for a fight, he made eye contact with the lead goblin just as a paralyzing jinx hit him, Harry looked at each goblin in turn as they fell from the invisible jinxes Ron and Hermione were desperately firing at them. Harry's neck was getting sore by the time the final goblin fell just a few feet from him, now that his path was clear he waved his hand at the doors and tried not to wince when he felt two knockback jinxes rocket past and hit the doors, sending them rocketing inwards.
"So remind me again, what's the plan once we get into Gringotts?" Tonks asked slowly
"The first step is to intimidate them so they don't look too closely at our disguises, you then demand to go to your Bellatrix's vault. When we get down to the vault we get the goblin to open the vault and try and get the… object without drawing suspicion from the goblin." Harry said
"If the goblin does suspect you, well you may need to imperious him to get back out as Griphook can't open the vaults anymore." Ron cut in
"Assuming all goes well we then use the turner and get out before Vold… He can get us." Harry continued
"Why don't we just go back several hours and break in before you-know-who knows about it?" Tonks asked
"We aren't entirely sure how a time turner will react to going back in time while already being back in time, it may only be able to go back 6 hours from first use so you can either go back one hour six times or go back six hours once… of course the time turner may be able to go back six hours every time but it's best we don't try it incase we're wrong." Hermione said
Harry didn't bother getting the goblin's name but whoever he was he didn't ask any questions and led them down to Bellatrix's vault, when he opened the vault Harry quickly glanced over everything and easily spotted Helga Hufflepuffs cup. Even if he wasn't looking for an item from a founder the dark presence it gave off was easy to detect.
When he tried walking over to the cup he accidently tripped over a chest plate and fell into a pile of coins, instantly the coins started duplicating and heating up, getting up clumsily Harry started wading through the treasure towards the cup. Behind him he heard Tonks imperious the goblin but as he couldn't do anything about it he ignored it, found the treasure had gotten so dense he couldn't go any further and the heat was starting to get painful.
Thinking quickly he drew the sword of Gryffindor and thrust the blade through the handle of the cup, he then waded back to the vault and Tonks had the goblin open the door. In Front of them stood what must have been every security goblin, before he could come up with a plan the sword was pulled out of his hands and he just caught a glimpse of Griphook running away with the sword before he was swallowed up by the other goblins.
Tonks pulled Harry to her and threw the chain around their necks and went back an hour, luckily they had managed to get out of the vault before they had seen the goblins as otherwise they would have been stuck in the vault for an hour.
"Where's the cup?" Tonks asked urgently
"Still on the sword!" Harry swore
"And Griphook has the sword" Tonks moaned
"Come on, we can't wait here as we will be here soon… if we wait a bit further up the path we should be able to avoid ourselves and stop Griphook after he leaves us…"
They needed to rely on Tonks' disillusionment spells since Harry had never learned it and Hermione and Ron still had his cloak, luckily they didn't see anyone the entire time
"So… since we have an hour to wait… fancy telling me what's so important about this cup?" Tonks asked after a moment of silence
Harry sighed and against his better judgement told her about the horcruxes and their hunt to destroy them, when he finished there was an uneasy silence which lasted until they watched their past selves wizz past on the carts.
"There we go… I guess we should keep an eye on the vault" Tonks said
Harry stood and shook his legs to get rid of the cramp that had been building up for the past hour.
He was about to go down to the vault when he felt a sharp pain in his scar
"Potter!" Harry turned and swore when he saw the real Voldemort and Bellatrix marching towards him, it was only Tonks' shield that stopped the first barrage of curses from Voldemort
Harry and Tonks started returning fire, in an even fight the two would have lost almost immediately however the caves they were fighting in provided lots of opportunities for them to dodge and hide. The rocks must've been magically enhanced as almost every spell just splashed against them rather than blow them up.
Voldemort had managed to push Harry and Tonks closer to the vault but the sounds of the goblin guards were getting louder, if the goblins started attacking them they would be crushed easily.
Just as Harry was about to lose hope a spell flew from behind Voldemort and sent Bellatrix sprawling forward, which gave Harry the opportunity to send a banishing hex at her before throwing the time turner chain over him and Tonks and going back by yet another hour. He was slightly alarmed when the time turner started lightly smoking.
He and Tonks took a moment to regain their breath and plan, Tonks even showed Harry some auror class shields. Eventually Harry's scar started hurting again and they heard the sounds of combat, they hid in a side tunnel and waited until Voldemort and Bellatrix went past before stepping out and attacking from behind, it was Tonks' spell that had sent Bellatrix forwards.
Voldemort seemed surprised to see them and now it was Harry and Tonks that were forcing him towards the guards, Bellatrix was noticeably slower and Tonks managed to hit her with a bone breaker that forced her out of the fight.
The fight was then interrupted by the Gringotts guards marching around the corner and pointing their weapons at the four of them, Voldemort let out a frustrated growl and grabbed Bellatrix before disappearing straight through Gringotts wards. As the guards recovered from the wards breaking Harry spied Griphook near the back of the goblins, the sword and cup still clutched in his hand.
Harry desperately pointed his wand at Griphook and cast expelliarmus, the sword flew out of his hand and over the heads of the guards. With reflexes honed from years of Seeker training Harry reached up and grabbed the sword, as soon as he had the sword Tonks activated the time turner and sent them back two hours.
Once again the world seemed to move in reverse until with a loud crack the world went back to normal, when Harry looked at the time turner the reason for the noise became obvious. The time turner was lying in pieces at their feet and the golden dust had escaped the hourglass and now covered the front of Harry's robes.
Turns out I was overestimating how many chapters this would take, there will only be one chapter, if I'm honest I'm not entirely happy with this chapter and if anyone has any suggestions to improve it I'll be glad to hear it.