The most gifted witch of her age
Hermione Granger is captured and imprisoned in the dungeons of Malfoy mansion. Alone, wandless, defenceless... Yeah, right! Characters belong to Rowling.
If you figure out the charm Hermione never got to use, please consider this fic to be M-rated.
The door clanked shut and she heard the bolts be drawn on the other side, heard the key in the lock and felt on some subtle level the wards be put in place. Hermione sank to the cold floor, her legs too weak to support her. She was prisoner at Malfoy Mansion.
She sat very still for a few moments, hardly daring even to breath. Then she cried a bit, because she was a lonely girl in a terrible, terrible situation, and they had threatened to do so horrible things with her. They hadn't let action follow their words however, something that - glad as she might be for it - on a deep, perverse level actually had made Hermione slightly disappointed. That V. dentalis charm had taken her quite some time to research, after all.
She blew her nose and looked around. The room that was her prison had probably been built as a store-room, judging from the empty shelves that lined the walls. It was damp and cold and she shivered in her thin dress. They hadn't given her a blanket. She hadn't got any food either, but at small sink with a tap at least provided her with water. A high window let the moonlight in, but it was far too small to be of any use for her even if the wards wouldn't prevent her to reach it - which they probably would. Just to test, she threw at few pebbles towards it and they were deflected before they reached to glass.
So, this room was not originally intended to be a prison, then.
The wards that held her were powerful, and they were intended to prevent physical forces. Of course, without a wand, she was unable to channel anything like the magic needed to break out of even an unwarded prison. Even if she had a wand, she wouldn't be able to overrule these wards. Not break them as such, anyway.
But perhaps modify them. Hermione threw a pebble at the door, and noted how far it bounced, and in which angle. So, the wards covered the door as well - she couldn't touch it. That meant that when the door was to open, the wards would either have to be momentary dispelled, or they would be designed to allow the door through - either way, the opening of the door would mean a laps of the magical field that kept the wards together. If she knew the strength of the wards and their polarity - she threw a few more pebbles - and just did a few arithmancical calculations, she would be able to find the focus point for the collapsing wards. A focus point she could use to feed her own spells.
If she only had a wand, that is.
Hermione sat down on the cold floor and produced a pencil and a piece of paper from her pocket.
If she was to have a wand, she would be able to put a very, very feeble spell in place in the focus point - feeble enough not to be picked up by the monitoring charms that undoubtly were placed on the prison - ready to feed on the energy of the collapsing wards the moment the door opened. If the wards were powerful enough - pebble, pebble - a spell fed by them would be able to create a counterforce strong enough to cause a breach in the wards, a breach that would trigger the wards own counter-spell defence, which would, when it made her own spell collapse cause a new focus point, where a new counter-spell charm would be fed magical energy, which if timed correctly would be able to feed the first spell, causing a feedback loop that, in time, would fall back on itself and cause the magical buildup to increase hundredfold.
"Time" in this case being measured in the order of parts of seconds.
By which time she would have power enough to bring down the wards altogether.
Power enough to keep whatever bastard was opening the door busy (apart from whatever interesting side-effects the collapsing wards would cause in the cell and - more importantly - its doorway).
Destination, Determination, Deliberation...
If she had a wand, that is.
And IF she were to, somehow, acquire a wand, she wouldn't have to be content with slipping away quietly. After all, there would be a lot of waiting time - and Hermione was not in the habit of sitting idle when there was work to do. Just like so many other prisoners before her, she felt the urge to leave a little memory - a little 'Kilroy was here'.
She watched the small sink with a calculating look in her face.
Why not one of her favourite special little spells?
That blue fire that she had been so proud of during her first year, portable and waterproof. But still able to burn.
Or left to smoulder in the water, until ignited by a magical spark - by which time it would have spread by the drain to the pipes below the entire house.
If she had a wand.
Hermione nodded to herself, that little satisfied gesture she often made when she had completed her homework and acknowledged herself of a work well done.
She plucked a strand of her bushy hair and, removing the lead from her pensile, put the strand in its place. Witch hair and ceder wood, a terrible wand at best; but a wand never the less. Determined, Hermione set to work. She had a long night before her.