It was bitterly cold, despite being early summer as Harry and Hermione lay under the invisibility cloak beside the Hogwarts gates. The sun had risen several hours ago but had yet to penetrate the thick morning fog. The gates were clearly visible to the two hidden observers but the path in either direction faded quickly into blank grey cloud.
Harry yawned loudly and Hermione elbowed him harshly in the stomach. They'd only arrived two hours ago – just enough for the damp air to have chilled her to the bone. Grindelwald had held the night watch alone, claiming that he wouldn't miss the sleep. He'd said something cryptic about the side effects of dark magic when she'd asked and turned the leaf under her shoe into a port key to return her to Nurmengard.
She knew that he hadn't slept during the day either, because he'd finalised details of how to break the Malfoy wards and had made massive headway with the horcrux issue. He had isolated the exact rune combination that selected half of the soul and they'd come up with several potential alternatives to isolate the horcrux from Harry.
She also knew he'd been up to something else, which he hadn't been telling her about. His magic roared with dark fury, spiking throughout the day with frightening intensity. She'd begun learning occulmency as a result, isolating their bond to dim her awareness and the resulting sickness. He'd made every effort to help her, providing texts which he'd leave outside her room. He'd also left others relating to runes, history of magic and transfiguration which she'd thoroughly enjoyed.
Her talk about the hallows had gone surprisingly well, she'd expected him to deny his interest or try to lie. Instead he'd just complained about how close he'd been to it without realising and admitted that he'd met Nicholas Flamel in the 1920's and been a little put off immortality. He confessed that it had been brilliant for the first decade after the ritual that he'd performed to preserve his youth, then a combination of losing his allies (he'd called them allies rather than friends, which Hermione found even more depressing that the fact he was talking about people dying) to war and knowing that those that weren't arrested or killed would soon pass naturally convinced him that eternal life wasn't worth it. He informed her that he had already decided not to repeat the ritual again, so as soon as the term on this one ran out he would age naturally again until his time came.
The days had faded into monotony by now, the Malfoys were frustratingly absent although by now Hermione was sure she'd be able to identify every other death eater for the court. She didn't know whether Voldemort was there as she hadn't seen him enter or leave. She'd even asked Grindelwald if there was any way for a dark wizard to apparate inside wards. He'd laughed at her and told her that wards had a nasty habit of keeping dark wizards out. He'd then taught her a spell, based off the patronus charm, that repelled dark creatures and anyone who had more than moderately tampered with the dark arts. He'd told her there was no equivalent to keep out light wizards.
Hermione jerked back to the present as footsteps crunched through the snow. Dolohov dragged a pathetic looking Draco Malfoy behind him up to the castle. Finally, they were having some success. She poked Harry to make sure he was aware, and readied her wand.
'The dark lord will deal with you, your dedication to the cause is severely lacking.' The older death eater growled, Harry and Hermione shifted into a ready position and Harry held three fingers up.
Malfoy whined something and whimpered as Dolohov jerked on his arm. Harry held up two fingers.
They passed infront and Harry jumped up, sending stunning spells shooting from his wand. Hermione followed a fraction of a second afterwards, her spell nailing Malfoy in the chest right as Harry's glanced off Dolohov's ear. It wasn't enough to knock him out but it dazed him enough that Harry's next spell caught him dead on.
They grabbed a prisoner each and disapparated back to Nurmengard. Hermione ended up in the cells, panicked momentarily, then remembered that Grindelwald had warned them this would happen if they apparated in with prisoners. She passed through the door as if it were mist and sent a Patronus up to the castle's master to come and get them. She peered through the bars into the cell that held Malfoy, just as Harry walked through his door with a shiver.
'Reminds me of walking through a ghost.' Harry stated, then he grinned at Hermione triumphantly. 'Well we got him; I can't believe it took a whole week of lying in that bloody ditch.'
'Excellent! An extra!' Grindelwald announced from the end of the hallway. He walked towards them with his arms spread, peering into the two cells. Hermione knew immediately that he'd been performing powerful dark magic whilst they were away. It seemed like the aura swirled around him, battering the shields Hermione had shakily built.
He cast a quick spell over the two death eaters and turned around to lead them back through the labyrinthine fortress to their rooms. The two light wizards shared a concerned look, worried that the dark wizard was so intent on concealing what he was doing.
He dropped them off at their rooms before retreating down the corridor and out into the arena. Harry jerked his head after him and Hermione nodded, running after him.
'Gellert!' She called out, he stopped, half way up the stairs of the auditorium and waited for her to catch up with a confused expression on his face.
'Is something wrong?' He asked when she got close enough to not have to shout.
'Yes, er, no...' She paused and tried again, 'Harry and I are just concerned about what you've been up to.' She finally managed to get out. Unexpectedly, the dark wizard broke into a wide grin.
'I've been cleaning.' He said by way of explanation. Dread pooled in Hermione's stomach because that could mean anything. Housework definitely didn't require magic strong enough to cause the power high he was clearly on.
'Here, come, let me show you.' He said, leading her off into the depths of the castle. They passed through the living quarters (which were much cleaner, she noted.) and the cell blocks without stopping. They stopped at a floor just above the ward room and he pushed open a door into a massive, well lit chamber. The only furniture was a desk, without even a chair, on which sat several glass jars full of something black, a glass cup and a cardboard box. He hurried over to the jars, carefully opening a lid and levitating something out. She couldn't see what the item was as he let it drop into the glass cup, so she dared to approach the desk.
He looked up at her and smiled in a way that she was sure was meant to be reassuring. It did very little to help, because at the same time she could feel him gathering his power. He held up the cup so that she could see the contents – a single black flea.
'I got the idea from the spiders but you can't alter the corpse of an inferi – they're resistant to magic of course.' He said this as if it should be common knowledge. 'So I considered the imperius, but it would be nearly impossible to effectively control that many life forms, especially for them to effectively fight. Then when I read that muggle book about the bear from your bag, I realised that if I could create a hive mind, they would all operate independently but I could influence them with a suggestion.'
Grindelwald waved his wand and his magic surged powerfully through the wand, sending a shockwave-like pulse through the room. The flea in the jar jumped to life and began to ruthlessly attack the glass.
'We needed an army to take Malfoy Manor,' He explained. The contents of the glass jars writhed and she realised they was full of bugs, all trying to break free to attack the cup.
'That's terrifying.' Hermione murmured, backing away uneasily.
'Exactly, see? Somnus!' he snapped, flicking his wand at the jars which obediently stopped their frenzied assault on the glass. 'We needed a distraction before we went into the manor, now we have one that doesn't put a single person at risk.'
He led the shell shocked witch out of the room, detailing how large they could grow the bugs, how they were linked to one another and he'd witnessed them perform coordinated attacks in his tests.
'Gellert?' She interrupted him mid flow. He stopped abruptly and she realised he was hoping desperately for her approval. 'I think it's brilliant.' She told him sincerely.