The punishment for my outburst was one of the worst I'd ever received. I spent days afterwards just drifting in and out of consciousness, and weeks after that struggling to do the simplest things, unable to make the trip into my secret potion storeroom - a purse with an Undetectable Extension Charm - to get something to help. My lessons with Lucius continued during this time, earning me punishment after punishment for not being able to do the spells I was instructed to. These often left me feeling as though I was just an inch away from death, and that any of my shallow breaths could be my last.

In the end, it was Narcissa Malfoy who decided that enough was enough. Apparently fed up with my near-constant passing out and leaving bloodstains in various places around her house, she persuaded Father that it would be best for me to be given some healing potions. She brought them down to me herself, silent and haughty, but removed the stoppers for me when she saw I was struggling with it. I gratefully drunk down the potions, and by the next morning, I was back to full strength.

My lesson with Lucius that day went well enough to keep me from further punishment, but it also got me thinking about the past few weeks, which in turn reminded me of just how powerless I was against the Dark forces my father commanded. Now that I was once again able to use magic without completely exhausting myself, I decided there were some spells I ought to know. So, as soon as Lucius' footsteps were far enough away from my 'room', I took my enchanted purse out from its hiding place (beneath a stone in the floor that would only open with a specific combination of spells), and climbed into it, setting up a charm to warn me if anyone was approaching my 'room'.

Down the ladder at the opening of the purse was a storeroom, potion brewing room, and kitchen all in one, with doors leading into yet more rooms on three of the four sides. I'd been working on this for years and years, creating almost everything with magic - mainly by transfiguring small stones and insects that had come into my cell. Not even sparing a glance to the shelves full of potions on one wall, or the cupboards of ingredients on the other, I pushed open the door straight in front of me, and headed into the room that lay beyond it.

This room - my library - was far larger than any room of Malfoy Manor, with shelves of books covering every inch of the walls, and even more in rows along the floor. In the middle were a number of oddly uncomfortable sofas and armchairs, each with a table or two nearby to hold books, glasses of water, or, if I was really lucky, some food.

A slight calm washed over me at the sight of the room after weeks of not being able to get to it. With a contented sigh, I went to find the book I knew would contain some spells that I really ought to have learned by now.

"Where is it...?" I mumbled, running my hands over the spines of the books. Then, with a triumphant, "Aha!" I pulled the right one from the shelf.

The title of the book claimed that it was 'A Comprehensive Guide to Combating Dark Magic'. Although I highly doubted that it was actually comprehensive, it certainly seemed to include a lot of useful spells. Unsure of which one I should start with, I carried the heavy, leather-bound book over to the largest table, and opened it to a random page.

"The Patronus Charm," I read aloud. "Incantation: expecto patronum."

I frowned slightly, trying to think of where I'd heard that spell before.

Expecto patronum... expecto patronum... oh! It was in Fantastic Beasts and Where to Find Them, in the bit about the Lethifold.

My mind content now I'd worked out that piece of information, I read on.

"The Patronus is one of the most powerful defensive charms known to wizardkind. The aim of this charm is to produce a corporeal Patronus - a silvery-white guardian in the form of an animal (the exact form will not be apparent until the spell is successfully cast). As a pure, protective magical concentration of happiness and hope, it is the only spell effective against Dark creatures such as Dementors and Lethifolds, and highly effective against many other creatures of evil.

"A successful Patronus Charm is achieved by thinking of a particularly strong happy memory, such as the day of your wedding, and performing the incantation. However, be warned that because of its difficulty, the majority of witches and wizards are unable to produce a Patronus. Some may manage an incorporeal Patronus, which resembles a mass or wisp of silvery vapour or smoke, but this is not a true Patronus, and while it will give limited protection, it cannot provide the power of a corporeal Patronus.

"The form of a Patronus may change during the course of a witch or wizard's life. Instances have been known where the form of the Patronus changed due to bereavement, falling in love, or profound shifts in a person's character. Because of this, some witches and wizards may be unable to produce a Patronus at all until they have undergone some kind of psychic shock, and others who were previously proficient in the charm might suddenly find themselves unable to produce one after such an event."

My eyes flicked back to the incantation, and I quickly fixed it in my memory, determined to teach myself the spell. I'd have to do it wandlessly, of course, but as that was the only type of magic I'd been taught over ten years of tutoring, I didn't think it would make the spell any more difficult for me.

Ready to start practicing immediately, I tried to think of a memory I could use, but my mind stayed frustratingly blank. I had plenty of bad memories - memories of anger, of sadness, of pain, of fear, and of death - but an uncorrupted happy memory was a rare thing indeed, and finding one strong enough to cast a Patronus would be a small miracle.

Eventually, after a lot of searching through my mind, I held my hand in front of me, and focused on the only truly happy memory I could think of - when I'd received my Hogwarts letter, and had thought I'd be able to finally escape the Manor.

"Expecto patronum!"

Nothing happened. I hadn't really been expecting it to, but all the same, I was disappointed; I hadn't practiced such an advanced spell for a while, so I'd forgotten that (unlike the easy spells my tutor had been 'teaching' me), I wouldn't be able to successfully cast it straight away. Taking a deep breath, I tried again.

"Expecto patronum! Expecto patronum! Expecto patronum!"

I sighed in frustration as my Patronus still stayed stubbornly nonexistent.

No matter, I thought to myself. I'll just keep practicing.