Bagsy didn't see Mezrielda in Transfiguration the next day. Tod was there and sat next to her, chatting pleasantly the whole lesson as if he hadn't played a mean trick on Mezrielda the day before. Bagsy couldn't bring herself to confront him, and when Tod managed to transfigure a string of hay into a piece of thread, she felt even worse about herself. She was a coward, a bad friend, and a poor witch, too. At least Tod was happy to give her tips on casting spells and didn't once make fun of her lack of ability.

She shared morning Transfiguration on a Friday with the Slytherins and the Ravenclaws, which she only really noticed when Winifred, a Ravenclaw, approached her after the lesson.

'We'll be assigned our first Herbology project next lesson,' Winifred said suddenly, appearing at Bagsy's side and startling her. 'I reaaaally wanna get a good grade, so I was thinking we could spend personal study time on Tuesdays to organise ourselves. We have Herbology right after, so we'd turn up to lessons ready to work and everything.'

Bagsy blinked – she hadn't expected Winifred to be so eager to work. Perhaps she sensed how much of a dead weight Bagsy was going to be. Bagsy smiled thinly. 'Sure. Sounds like a plan.'

'Great.' Winifred gave her an encouraging pat on the back. 'See you in Charms on Monday. Can you not get the whole class banned from using wands again, though? If it's not impossible for someone like you.'

Bagsy looked at her feet uncomfortably as they walked along. 'Sure…'

'See you!' Winifred swiftly spun around and walked away from her.

'Wait! Where are you going? First-years have personal study now!' Bagsy called after her.

Winifred turned to look at her, walking backwards, hands on the back of her bald head. She shrugged. 'I've got better things to do.' A few other Ravenclaws flocked over to Winifred and the group disappeared around a corner with laughter. Bagsy shook her head, then headed for the library.

Mezrielda wasn't in the library, either, and Bagsy was beginning to worry.

Bagsy was half way through taking notes on a Charms book she was reading – determined to cast at least one spell next lesson – when she found her focus leaving her. No one had taken any registration, and the young librarian didn't seem to be paying any attention, having resigned herself to a loud environment when the first-years had personal study. Bagsy noted a lot of first-years simply hadn't shown up, Winifred included, and no one seemed to be looking for them.

She quietly closed the book Charms for Early Years using the parchment she'd been taking notes on as a bookmark. Leaving her belongings under the desk and glancing over her shoulder at the young librarian who was shuffling down an aisle, holding up books that then floated to their place, Bagsy crept out of the library. The only thing on her person was her hornbeam wand and her map.

She went up and down every moving staircase she could find, politely asked portraits if they'd seen a girl with messy black hair, and even gave a tentative glance down a dark passageway hidden behind a tapestry by a statue, what must have been the wind made a distant, eerie wailing noise.

If Mezrielda was down there she wasn't following.

Bagsy checked as much of the ground floor as she could manage, then moved on to the second. She peaked under doors and through key holes, seeing classes mid flow, strange creatures in cages, odd brews and vails of what must be the potions store cupboard, and a collection of rusty old swords that curled up in to balls and unfurled out again. She didn't see Mezrielda.

Bagsy couldn't bring herself to check any spiral staircases she came across, remembering the endless stairs she'd been trapped in the previous Monday, but as she was passing by some spiral stairs, shuddering to herself, she heard soft crying. Walking as quietly as she could, Bagsy approached the door to the third floor's bathroom and pressed her ear to it. There was someone in there.

She got on to her hands and knees and squeezed her face next to the gap between the door and the floor, seeing someone's shoes, but not who it was. Standing back up, she raised her hand to knock on the door.

Her hand froze. What would she say? What could she say? Bagsy knew she was fantastic at putting her foot in her mouth, so she took a second to think on her words. She lowered her hand, feeling foolish for searching for Mezrielda when she wasn't prepared, only for the door to open and the subject of her search appear in front of her.

Bagsy noticed Mezrielda's eyes weren't red in the slightest, and there were no signs of tears on her face. Mezrielda frowned deeply at her, shoulder barged past her and hurried off down the corridor, her messy black hair still knotted beyond repair. Why Mezrielda hadn't simply gone to Nurse Jones and asked for him to fix it Bagsy didn't understand. Maybe it was pride.

Bagsy sighed, getting her map out once again, and started walking back to the library. She progressed onwards like that for a bit, nose in her map, until she suddenly felt the hairs on the back of her neck stand up. Looking around herself Bagsy saw the same long, torch lit, sloped corridor with a red carpet the darkness and suits of armour had appeared in before.

She felt her muscles freeze. There was a noise at the other end of the corridor – an uneven set of feet thudding down on the red carpet. Bagsy couldn't move, only watch, as a tall, large shadow fell on the wall as the owner of the footsteps came around the corner. Her mind instantly went to the suits of armour.

Bagsy let out a breath as Professor Blythurst, looking like a large cauldron draped in black robes, shambled towards her.

'Bagsy?' he said in confusion, stopping momentarily before continuing towards her again. 'You should be in the library,' his deep, croaky voice grumbled.

Bagsy bowed her head. 'Sorry, Professor.'

Blythurst sucked in a raspy breath. 'I'll let it slide. Wouldn't want to take points from Hufflepuff, would I?'

'No, sir,' Bagsy agreed. Was Blythurst head of Hufflepuff? It would make sense, she supposed, he did organise the Hufflepuff table at the beginning of term feast, and had gone into the Hufflepuff common room afterwards.

'Hm.' Blythurst inspected Bagsy with his unevenly sized eyes. 'Run along then. To the library, as quick as you can.'

Bagsy nodded and broke in to a jog but stopped after a few paces. 'Professor Blythurst?'

Blythurst grumbled something and, with some difficulty, turned to face her. 'What?'

'What do you teach?' Bagsy had tallied what the other professors taught in her head, her hopes rising.

'Potions, of course. It's on your timetable.'

Bagsy hadn't noticed teachers were listed on her timetable. 'Oh,' she said lamely, then, 'um, professor, do you know any potions that can untangle things? Only, I-'

'Of course, I know a potion for that,' Blythurst cut over her, 'but it's beyond your level, first year. In your later years I might consider divulging them to you. Now run along. The library, Ms Beetlehorn,' he prompted her, turning and walking steadily down the corridor.

Bagsy ground her teeth together. She had no hope of figuring out a spell to fix Mezrielda's hair if Mezrielda herself couldn't do it, and she wasn't about to ask Tod to undo it, either. Forming a plan, she raced back to the library, grabbing her timetable from her bag. Out of curiosity she looked for the list of teachers. Sure enough, there was a list of what teachers taught what subjects. Blythurst was listed by Potions, below Professor Wattleseed, for Herbology, and above Professor Hilkins, for Transfiguration. Reading her timetable, she confirmed that after Lunch she had double Potions. Blythurst said the de-tangle potions were beyond her level, but if she could show him otherwise in class, perhaps he'd be willing to teach them to her.

Bagsy ran from one shelf to the next, grabbing books twice the size of her head, smaller than her palm, or made of marble, glass or wood. One of them kept asking her name – Bagsy felt answering was a bad idea.

She piled the books high on the desk she was sitting at and poured through them, ignoring her rumbling stomach when Personal Study ended, and Lunch began. She read about ageing potions, hiccoughing solution, muffling draughts and garrotting gas. She read about foxglove, and its use in pompion potions, that turned your head into pumpkins. Bagsy's mind absorbed all it saw, fitting together the pieces as she read, learning how one thing made a potion do this, and with other ingredients made it do something very different. Powdered griffin claw when combined with salamancer blood strengthened a person, but when paired with lionfungus spines prevented a drinker from being able to sleep for many days.

The most interesting thing by far Bagsy found in the reading meant for higher years in potions.

In Beyond the Fundamentals: What Makes Potions Bagsy found a long, and complicated, explanation for how potions functioned. It was based on the fifth exception to Gamp's law of Transfiguration, whatever that was. It read that certain magical effects couldn't simply be transfigured into a potion but had to be physically put there. That is, a magic user couldn't transfigure some water into Polyjuice potion. Instead, the Polyjuice potion had to be brewed from scratch.

The book emphasised that three key components had to be present for a potion to even be a potion and work. One, there had to be a foundation, which must always be a physical substance. This substance would be the basis for the potion and have the biggest impact on what the potion would end up doing. Two, there had to be an additive or additives, which also had to be physical substances. These allowed for the properties of the foundation, when mixed with them, to have magical effects. Three, the last component, was a binding. A binding could be either another physical substance that forced other substances together, or something non-physical to merge a potion, like stirring or a spell. Either way, the binding acted as a method of combining ingredients to make one substance – a potion.

Bagsy, for all her inadequacies, felt like she understood what the book was saying. Given that she understood this basic principle, she felt confident that, whatever they were tasked with in potions, she could improvise her way to victory.

The potions classroom was in the dungeons and Bagsy regretted not wearing something warmer to the lesson. She also regretted paying attention to the glass jars lining the shelves of the room – a container of grey eyes stared back at her and she swore some of them blinked.

A statue of a Gargoyle sat in the back corner, water spewing out of its mouth and into a basin, cauldrons stacked around it. Luckily, Bagsy had her own cauldron. Unluckily, as she sat down, she realised she'd left it in her room. Her plan wasn't going off to a great start.

Blythurst, who limped into the classroom and shuffled to the front, narrowed his odd eyes at Bagsy as she sheepishly grabbed a spare cauldron from the front. 'Don't make a habit of this, Ms Beetlehorn,' Blythurst rasped, chalk tapping on the blackboard as he wrote out instructions.

Bagsy took a seat at the front and arranged the cauldron and her potion making kit neatly in front of her. Her hands were shaking with nerves, but it didn't feel bad. She was facing a challenge – one she was determined to overcome.

Blythurst checked everyone was present, his voice growing more croaked with each name until he'd cough a horrible, wet sounding cough and continue. Once he was done, he tapped a long, twisted black wand on the black board. 'Follow the instructions. No talking. Focus.' Blythurst shot a strong look at Arice Allthorn who'd been whispering to his neighbour. The larger of Blythurst's eyes looked ready to pop out – Bagsy made a note to never disobey him, worrying she'd wither under his glare.

Blythurst sat down at his desk with a loud sigh, placing his large feet on a stool and leaning back. Bagsy hoped he wouldn't shut his eyes and fall asleep, she needed him to see her do well.

Bagsy looked at the instructions and her heart soared – they were to brew Wiggenweld potion, one of the potions she'd read about during Lunch. She collected the ingredients she'd need from the shelves around them, able to identify them from the books she'd read earlier. A few students, seeing her confidence, copied. Others didn't know what ingredients to take, or that they were even allowed to take them, and stared hopelessly at their empty cauldrons. One girl stirred thin air while staring blankly into the distance.

Bagsy was determined to do well and didn't think much on Blythurst's hands-off, drop-in-at-the-deep-end approach to teaching.

Wiggenweld potion had 19 steps in total and changed colours more times than Bagsy could count. She added salamancer blood, lionfungus spines, flobberworm mucus, syrup water and boom berry juice in different amounts and with specific stirrings in-between.

As she worked, she tried to guess which ingredient the foundation was. It was probably the salamancer blood, she reckoned. The additives she was sure were the lionfungus spines, flobberworm mucus, syrup water and boom berry juice, or was one of those the binding? Could you have more than one binding? Bagsy couldn't remember reading anything on that.

Maybe the stirring and the syrup water were both bindings, or perhaps it was the boom berry juice instead? Bagsy also wondered, looking at a vial of salamancer blood, if which foundation a potion had limited what it could do, or if, with enough additives, any foundation could achieve any result. Would the potion really have a foundation anymore in that instance, or only additives?

Bagsy became so enwrapped in her own wonderings she nearly over-brewed her final solution and hurriedly tried to turn the flame off below her cauldron. In her rush the old cauldron, which was severely dented on the side and unstable, toppled on to the floor, and Bagsy's potion spilled on to the stone – ruined.

Tears pricked her eyes as realisation hit her, her train of thought replaced with a swallowing feeling of failure.

'Profess-' one of the students was mid-way alerting Blythurst, but the man was already staring at the spilled potion. With a swift wave, and before the student could get the full word out, the potion disappeared.

It was the end of the lesson and Bagsy didn't have any more time to prove to Blythurst she was ready to learn the potion to de-tangle hair. She sluggishly packed up her things with the other students, feeling miserable.

Arice gave her a sympathetic smile. 'It was going pretty okay. You know, before it spilled, and all,' he offered kindly. Bagsy smiled gratefully back at him, but her heart wasn't in it. She was the last to leave, trudging glumly at the back.

'Ms Beetlehorn,' Blythurst called from the back of the class.

Bagsy gripped the strap of her satchel and turned to look at him. She sniffed nervously. 'Yes, P-Professor?'

'You spilled your potion. Why?' Blythurst fixed his eyes on her, his crooked mouth drawn into a thin line.

Bagsy tried not to stare at the ugly scar going across his face. 'I didn't mean to sir, honest. I was trying my best and-'

'I don't care,' Blythurst cut across her. 'Answer my question, Ms Beetlehorn. Why did you spill your potion?'

Bagsy stood silently in confusion, whilst Blythurst seemed happy to wait and sat back in his chair with a sigh.

She furrowed her brow and looked at the ground before realising what Blythurst was asking. 'Oh!' she said, smiling and looking back up. 'I rushed. I moved too quickly, I wasn't careful, and I knocked my potion over.'

Blythurst's eyebrows shot up, the left one missing half its hair. 'Well done. Yes, you were careless. I was watching you. You clearly have a talent for potions, Ms Beetlehorn.' Blythurst dragged in an ill breath. 'But – Potions requires a steady hand and a focussed mind. You can't rush magic, or try and cut corners, unless you wish to welcome unintended consequences. Self-evaluation is the best path to learning, so it's good you recognise this flaw.' He nodded approvingly. 'You are much better than I'd expected. I'd been told you had little magical talent.' Blythurst's eyes narrowed. 'But I reckon you're a specialist, Bagsy. A good guiding hand and you'll be well on your way, I bet.'

Bagsy's eyes widened. 'Sir?' she didn't know what to say. This was the second time a teacher had complimented her. Then again, Blythurst was probably just biased in favour of Hufflepuff and wanted an excuse to give them more points.

'Come back to your desk. I'm going to show you how to make tangle-teasing solution.'

Bagsy could have jumped for joy, her plan had worked. She'd tricked Blythurst into thinking she was good at potions, and guilt poked around the back of her mind, but it was worth it to get what she needed.

An hour later, and after harsh instructions and brutal criticisms from Blythurst, Bagsy was in a state. The heat of the cauldron had made her abandon her school robe in favour of just her button up white shirt, whose sleeves she'd rolled up to her elbows. Her hair was more of a mess than usual – if any of this solution was left over she might try it on herself. But, as much of a mess as Bagsy was, trapped in a tear shaped glass vial, and stoppered with an iron cork, was what Blythurst informed her was tangle-teasing solution.

'Now,' he croaked, sitting down with a huff and massaging one of his legs. 'That stuff will mock whoever uses it mercilessly. It's not called tangle-teasing for nothing.' Bagsy looked from Blythurst to the misty blue liquid fearfully. 'It's harmless. Nothing a bit of tough skin can't handle, and it will get rid of tangles, no question.' Blythurst took a shaky breath and a coughing fit racked his body. He groaned, as if in pain, 'get out of my class.'

'Yes, sir. Thank you, sir,' Bagsy squeaked in a mixture of excitement, awe, and horror, before collecting her things in a whirlwind of robes and brown messy hair.

'Ms Beetlehorn!' Blythurst cried. Bagsy stalled. 'We just discussed this!'

Bagsy blinked at him. 'Oh! Not rushing!'

'Yes, for crying out loud. Don't go spilling that potion, too.'

'Sorry, sir. Thank you, sir.'

Blythurst nodded uninterestedly and shooed her with his large arm. Bagsy hurried in a not-too-hurried manner out of the room, stowing the potion in her satchel, a smile breaking out on her face.