"I think I've finished!" I announced to my best friend Lily Evans, holding the glasses into the air in triumph. "What should we call them?"

"I don't know, Issa. You always come up with the names for your inventions. My names will just ruin the beauty of them." Lily replied with a smile.

I was sat at my work desk, wand in hand and the glasses I had just created balanced on the table in front of me. Lily was curled up in one of our squashy blue armchairs reading a potions book so that she would be up to date when we got back to Hogwarts. She was staying with me over summer whilst her parents were holidaying in Romania. There was only a day of holiday left before we had to get on the train and go to Hogwarts for our final seventh year. I sat down on the hard stool, staring at my creation, wondering if it worked. Suddenly, I jumped up, grabbed the glasses I had just made, and thrust them into Lily's hand.

"Put them on and tell me what you see!" I cried, clapping my hands together and watching her hopefully.

She laughed and examined the glasses I had made with admiration. "What are they for again?" she asked me, carefully balancing the glasses on her nose.

"Wrackspurts," I answered and she gave me a quizzical look. "I've told you about them before! They're little bugs that fly into your head and make your brain go fuzzy. Not everyone knows about them (or believes in them) because they live inside your head and they're invisible. You should be able to see them using the glasses... Can you?"

"I can sort of... It's not very light though; try making the lenses another colour!" she said, enthusiastically.

I took them back from her and placed them back on my working table. I knew the spell to change the colour of them, but I had only used it once and it had slipped my mind. There was no doubt Lily knew the perfect spell. I glanced over to her, but she had picked up her book again and I didn't want to disturb her too much. Eventually I decided that I couldn't remember the incantation, so I headed through the door of our library, positive I'd find it there. My mother and father brought home a lot of books from their travels and couldn't fit them all in their bedroom so turned an old lumber room into a library. I loved that room the most, over all the rooms in the house (including my own), and could spend hours flicking through the pages and learning new things. These books helped me a lot, particularly with my experiments, because many of them had spells and charms in. I found a book named All the Spells you Should Know about Colours and brought it back to my working desk.

I would have found the colour-changing charm quicker, but I stopped to read about a spell to make your cat's fur continuously change to every colour of the rainbow over and over again until you took the charm off. With a promise to myself that I'd test it on Clove, my kitten, when I next had the chance, I turned a few pages and spotted the Colour-Change Charm. Multicorfers. How had I forgotten – I'd only used it a few weeks ago. I pulled my wand from the pocket of my dungarees (I always wore muggle clothing when I was out of Hogwarts) and held it out in front of the glasses.

"Multicorfers!" I yelled.

A jet of light emerged from my wand and when it was gone, one lens of the glasses was pink, and the other one was blue. The frame of the glasses turned a purple sort of colour that I thought I could change into a pattern later and make it more attractive. Instead of asking Lily to check they worked for me, I put them on and gazed through. I saw roughly ten tiny creatures zooming around Lily's head.

"Lily, Lily, Lily!" I shrieked in excitement, ripping the glasses from my eyes. "I see them! The wrackspurts!"

She shut her book and grinned at me. "Can I take a look? They're very pretty."

Lily never failed to compliment whatever I had made, even if she thought it was completely ridiculous. I handed them over to her and she peered through.

"Ooh, I see you, but also a few dots flying in and out of your ears," said Lily slowly. "They must be the wrackspurts!"

"That's right!" I answered.

"Wow, that's cool," she sat up a little straighter in her chair and stared at the glasses. "Those are some spechaspecs..."

My eyes widened. "What did you just say?"

"Those are some special specs."

"But it sounded like... Scetrespecs..." I murmured, thinking about the way the words fitted together. "I like it! That's the name! We'll call them spectrespecs."

"Nice name."

I sunk into a chair near hers as she handed them back to me and I began to think aloud. "What shall I make next? I was thinking a device that could locate nargles. You know, so you can tell if you're near some. They're best avoided. I think we're just lucky we haven't come across any recently. What do you think?"

But Lily wasn't listening. She was by the window where a faint tapping noise was suddenly audible. Intrigued, I stood up and hurried to her. The tapping noise was being made by Griffin, her owl, who had a letter wedged in his beak. Lily fumbled with the latch, but eventually managed to get the window open far enough for Griffin to swoop in.

"It's already getting cold out there." Lily commented, glancing out the window as she took the letter out of Griffin's clutches. She sighed and tore open the envelope. It was a long letter. "This'll take me a while to read... It's from Sev."

I smiled to myself and headed over to the sofa. It wasn't ideal for inventing anything, but it was a lot more comfortable than my work bench. It took Lily five minutes to read as I sketched out ideas for a nargle locator. When she finally finished she plonked down next to me. "Sev wants to know if we'll come to Diagon Alley today," Lily explained. "He's over there now buying stuff for school. Shall we go?"

"Sure," I replied. "But, he didn't spend that whole letter asking us to Diagon Alley did he?"

Lily giggled and her eyes lingered on the letter in her hand for a second. "No, it's just we haven't been in contact much this summer because I'm here with you. He's been... Updating me."

I shifted in my seat and stood up. "I'll leave a note for my parents."

Together we left the living room/work room area and ended up in the hallway. Lily stood behind me as I flicked my wand at the empty picture frame in front of me. Suddenly, there was an image of me as if I was staring at my reflection in the mirror.

"Hi, message Issa," I said to picture. She waved back. "Can you please leave a message for mum and dad to let them know I'm out at Diagon Alley with Lily?"

The picture gave a curt nod. It was a way my family had of contacting each other. Although the picture could only say the message it was programmed to speak, it was very useful. It was a creation of mine that I thought might come in handy sometime.

"You're amazing, making that." Lily gestured to the photo.

I shrugged and said nothing.

We used floo powder to get to Diagon Alley because Lily had only recently passed her apparation test and it made her quite giddy whenever she tried. I personally preferred to apparate because I didn't like the feeling of travelling by floo powder, but all the same we went to my fireplace and both took a handful of glittery powder. I was going first.

"Try not to get your words wrong." Lily pleaded, clearly remembering the last time we had used floo powder and I had ended up in Hogsmeade instead of her house.

"I'll try," I promised and hurled the powder into the fireplace. The flames became a rich, warm, green colour which I stepped into. "Diagon Alley!"

Every time I travelled with it, I tried to brace myself for the horrible feeling of travelling by floo powder, but never could. The ground was suddenly gone from beneath my feet and I was whirling around catching glimpses of fireplaces and hearing snippets of muddled up conversations that didn't make sense. I preferred to have my eyes open, even though it made me feel sick and finally, a few minutes later, the whirling sensation slowed and I prepared myself to slam into the street.

After I had ducked through the fireplace and was standing outside Florean's, I leant back against the glass revealing the display case of ice cream choices. Lily showed up five minutes later later looking flustered and I noticed her usually-perfect fiery hair was slightly messier than normal. "I ended up in the wrong place." She admitted and I didn't press her for more details.

"So where are we meeting... Sev?" I asked tentatively. I never knew whether I should call him Sev or Severus. We weren't very close. I didn't like the gang he was in. The Death Eaters.

Lily didn't seem to notice my slight hesitation. "The magical menagerie," she answered, pointing across the road. "He must be getting a pet."

Together, we squeezed through the crowds of people towards the strong scent of animals, coming from the other side of the street. We entered the shop and the moment the door had swung shut behind us, the noise coming from outside was gone and replaced with chirruping, mewing and squeaking. We passed two Hufflepuffs in our year (who grunted hellos to us) and found Severus bent down, staring avidly at a large tarantula scuttling around. Lily made to tap him on the shoulder, but a boy in Slytherin got there first. Lily and I exchanged glances and hid behind a large cage full of nifflers to watch what was going on. They began talking in hushed whispers. The most we heard was the words 'Death Eaters' and 'Dark mark' and when I looked back at Lily, she was dismayed. I think we were stood there for around ten minutes and finally, when she obviously couldn't take it any longer, Lily marched out from behind the shelf and made sure he could see her. I lagged slightly behind.

"Hi, Sev!" Lily said, a little too enthusiastically so it seemed forced and Severus stood up so quickly that he tripped slightly on his robes. The Slytherin boy glared at us as he left.

"Lily," he cried and then, much less excited and happily (maybe even a little disappointed), he added, "And Isis."

I waved shyly, but said nothing. Around him, I always felt as if I was the only thing standing in the way of his and Lily's friendship being even stronger and he didn't want me around. It was likely to be true.

"So, you were looking at this tarantula for a pet?" Lily said slowly, gesturing half-heartedly at the spider that had just clambered onto Severus' hand. He brushed the tarantula away, spluttered and began mumbling protests, but Lily cut him off. "That would be cool."

Severus looked startled for a few seconds, but regained himself in time to say, "Yeah, yeah I'd like a tarantula maybe. I'm still thinking."

"OK, so you won't be buying any pet just now?" Severus shook his head. "Well, we could all go to the joke shop to give you time to think?"

He looked relieved to be off the awkward subject of a pet tarantula and blurted out, "Oh, yeah! Gambol and Japes have got in these new sugar quills where apparently the flavour lasts up to a year instead of those other ones that you could only use for a week max."

We spent a good part of the afternoon in Gambol and Japes. They had had an extension in their shop so there was lots more room for more items, which meant there was more to do. Severus became more relaxed then he had been in the magical menagerie. Afterwards, we went to the Leaky Cauldron where we spent the remainder of our time in Diagon Alley. I noticed that sometimes Lily seemed to be forcing a smile or speaking so ecstatically it didn't seem quite right. As usual, around him I didn't speak much. When the sky was darkening and people began to file out of shops as they were closing, Severus walked us back to the fireplace we had arrived in, even though we had decided we'd apparate home.

"So, er, I'll see you on the train tomorrow," he said. "I might have a new pet. I'll save us a carriage."

"Actually, Sev, maybe not," Lily replied, apologetically. "I forgot to mention... I'm head girl. Head boy and girl have to go in the prefects' carriage for some of the train journey."

"Oh... You forgot to mention... Well... That's fine."

"But, don't worry! You can save me a seat somewhere with Isis and then I'll probably come back about halfway through the journey."

Severus couldn't hide his disappointment. He muttered a goodbye and stalked back off to the magical menagerie. Lily and I apparated back to my house, only when we arrived realising how tired we were. My parents were back in and they greeted us as we trudged up the stairs to my room where a spare bed was set up for Lily.

The pair of us were both sat cross-legged on our beds, having washed and got into our pyjamas. I was casting random spells at my pillow, making it change size, shape and comfiness until it was perfect. Lily was back with her potions book. I peered over at her and saw she was on one of the last pages.

"What did you think about Sev and the other Slytherin boy?" I asked suddenly, not even realising I had said it until a few seconds later.

Lily had just finished the book which she shut tightly and slipped under her bed. Then she lay back on her pillow and pulled the duvet over her body. It took her a while to answer. Eventually, she said, "I don't know... Not great, I admit. I mean, I've never been a fan of his Death Eater gang, but they never used to be so... Well, their gang seems to be getting a lot more... serious. It's like they're taking it too far. It scares me a little bit. And Severus is changing. He's not been himself lately and I don't like it at all. I wish he'd just open up and tell me what's on his mind right now because I used to be able to tell, but now I just have no clue. You know what I mean?"

"Yeah," I sighed. "Yeah I do."

We spent a few minutes in silence and then I blew out the candles and Lily noxed her wand so it was pitch black. I curled up in my bed and shut my eyes, thinking about what Lily had said. Her friendship with Severus seemed to be falling apart. Lily's breathing became slower and heavier and I couldn't sleep. My last thought before I finally drifted off was realisation that Lily, for the first time I could recall, had not called Severus 'Sev'.