Hermione's first week went reassuringly well. Mostly because she spent the best part of Wednesday sat in the library surrounded by all the pieces of paper she had gathered over the previous couple of days. There, she had worked out a timetable which would mean she could study for and take her charms, transfiguration and arithmancy NEWTS before the Christmas holidays, while also managing her teaching load and having a bit of relaxation time. The latter wasn't something she had prioritised before the defeat of Voldemort, but nowadays she saw the value in having time off from her work and studies. She still had the problem of feeling constantly cold, but the addition of a layer of black professor's robes over her usual clothes and George's sweater had helped a bit.

Like many of those who had survived the second wizarding war, Hermione often found herself counting her blessings as she walked around the castle these days. She loved teaching, finding a lot of joy in the enthusiasm of the tiny first and second years, but was slightly nervous at the thought of one day teaching the older students, some of whom were nearly the same age as her. As downsides went, Hermione could live with that. Her rooms were cosy and pleasant and meals were almost more enjoyable at the teacher's table, although Hermione missed the camaraderie of sitting amongst a whole horde of people from her house. It was nice to chat to Neville and Charlie at lunch and dinner in what Neville had come to call the Gryffindor wing, although Charlie never seemed to make it in time for breakfast and was, as a consequence, always starving at lunchtime.

"Would you like me to send Polix over in the mornings with some sausages for you?" Hermione had asked him one day towards the end of their first week. "If you're struggling to get up in time for breakfast, I mean?" She didn't mean it unkindly. It was a genuine offer of help, but Charlie didn't take it well.

"I'm fine," he said, rather grumpily. "Just not hungry."

Hermione doubted that. He was a Weasley, after all, and the ability to eat twice as much as any other person and yet remain toned and gorgeous seemed to be an ability that most of them carried in their genes. And surely his fit, muscled frame and active lifestyle – not that Hermione spent too much time admiring his body, but it would be rude to look away when talking to him – required a good amount of food to sustain.

Charlie's mood wasn't that great in the evenings either. He seemed tired and careworn after the first couple of days, which got Hermione's attention. She hadn't spent much time with Charlie, in contrast to his other siblings, but she had always found him to be cheerful and friendly. She contemplated talking to George about it, but decided that the first step, in time honoured Hermione fashion, would be to do a bit of research and see if she could figure out what the problem was.

As projects went, it was probably the simplest she had ever undertaken. To be fair, the location of her room had given her a head start in the shape of a half-formed thought which had been floating around in her mind for most of the first week. Having noticed that her ceiling tended to glow for most of the night, it was a short leap to decide to wrap up even warmer than usual in the evenings in order to sit by her window to read or study and, at the same time, investigate the source of the light.

The answer was staggeringly simple. As each day began to darken, Charlie would head back to his hut and immediately add several logs to his fire, making it into a hefty blaze. Hermione could usually just make out the shape of the dragon keeper sat on a nearby log.

That wasn't the surprising bit though. Hermione enjoyed a good campfire herself. No, the surprising bit was that, no matter how late Hermione watched him, Charlie never seemed to go to bed. Hermione never managed to outlast him and, on the occasions that she woke in the night, she would peer out of the window to find that he was still there. No wonder he never made it to breakfast, she thought. Was he an insomniac? If so, there were potions he could take, although perhaps he was one of those people who preferred to avoid them if he possibly could.

Hermione was pleased that she had solved half the mystery, but clearly she couldn't stop there. She decided the next day that she would approach Charlie himself before talking to George, Fred, Neville or perhaps even Ginny, and set herself the task of chatting with him after dinner that evening.

Charlie was on a mission of his own though, and had rushed off to his hut after their meal. Hermione shook her head at Neville's suggestion of a game of cards, telling her friend that she needed to study, and wandered back to her room. If Charlie wouldn't stay and talk to her, then clearly she needed to go to him.

Back in her room, Hermione rifled through the wooden gift box of stationery items that George had sent with her to Hogwarts. Pulling out one of the matched pairs of 'twinchat' parchment pads that she loved so much, Hermione wrote a quick note on one and gave the other to Polix. "Could you take that to Charlie please, Polix? He's over there, by his fire. I know it's not far, but it'll save me going out in the cold..."

Polix would fly anywhere for Hermione. He was pretty keen on visiting Charlie too, as the burly, kind animal lover was well known amongst the Hogwarts owls for always having a great selection of treats which he shared generously. Just a few minutes after he had left, a note began to appear on her pad.

"Hi," Charlie had written back.

Well, she thought. He had never been one for long chats, but at least it was a start.

"Are you OK?" She scrawled, and then wished she had thought that through more. It was always such a pointless question and she never knew how to answer it herself on days when she didn't feel on top of the world.

"Fine," Charlie wrote back. Well yes, she probably deserved that. She needed to be a bit clearer. Better still, she needed to talk to him in person. Biting her lip in thought, she added another line.

"Can I visit you? Want to ask you something. Do you have a floo connection? I've got a fireplace in my room and it would save me walking over in the cold."

She watched her pad as he wrote again. "Yes, but it's only internal to Hogwarts. It's still set up as 'Hagrid's hut'."

"I'll be there in a few mins," Hermione wrote. "Need to put on more clothes."

When she arrived, the hut itself was dark; Charlie was clearly still out by his campfire. She whispered 'lumos' to light her way through his cabin but then extinguished it almost as soon as she exited the door. The glow of the fire that she could see from her window was merely the tip of the iceberg. Charlie had a massive blaze going, and the trees around his pumpkin patch were filled with magical lamps. It was almost like daylight. But he must have cast some sort of light shielding spell around his camp to keep it confined, because Minerva would certainly have investigated the source of the illumination otherwise.

"Charlie, what's going on?" Hermione asked gently. This clearly wasn't normal. "Are you having problems sleeping?"

The older wizard shrugged. "Yeah, something like that." He took a pull on a muggle beer. Hermione wondered if that was allowed, but suppressed her desire to ask. Instead, she sat on the log beside him and gently touched his arm.

"Insomnia?"

Charlie shrugged again.

Hermione sighed, realising that he wasn't going to make this easy. But his responses so far had confirmed to her that something was bothering him. Well, she wasn't afraid of silence. Or of having a bit of time to think. She gently rested her hand on Charlie's leg and it occurred to her only after a few minutes that he must be feeling really quite rubbish as he had neither commented on that nor flirted with her. But after a few minutes her thoughts coalesced and it became clear that she was going to have to push him a bit.

"Please talk to me, Charlie; I'm worried," she said quietly. "It's obvious something's up. You haven't been yourself at all over the last few days, and I don't think you're sleeping." She rubbed his leg gently with her fingers and he reached down to take her hand; an acknowledgement of their friendship even in his sour mood. "We've all been affected by the war, you know, and it's nothing to be ashamed of. Me, I'm cold all the time, and I get palpitations if something happens unexpectedly. George has nightmares about nearly losing Fred, and Fred is terrified of anything falling near him; it's a bit of a problem when things fall off the shelves in the shop..."

Charlie nodded. He knew all of this, and he knew rationally that it was OK to be afraid. But as the second eldest son in a big family, it had been his job to be the lieutenant who supported Bill and he had always tried to be a strong leader for the others. Merlin knew that Bill had been a big act to follow in that respect.

But Charlie also knew that he had barely slept for a week and he couldn't go on like this. For reasons that he never clearly understood, something shifted inside him and he decided to drop his stubbornness and tell the concerned little witch the truth.

"I'm not so good in the dark these days," he admitted. If not for the rosy-cheeked glow that the big fire had already given his face, Hermione would have seen his blush. But she had spent enough time with his brothers to know it was there and that it was kinder to pretend it wasn't.

"Is that a new thing?" Hermione spoke gently.

Charlie took a deep breath. "Since the final battle. I got caught in some of the twins' Peruvian darkness powder and a death eater threw a nasty spell at me." He showed Hermione a scar on his arm, and she touched it gently with her fingers. "I didn't see him in the dark. If I had been a few inches to the left … well, I wouldn't be here now. I suppose it all got linked together in my head somehow and I've struggled with being in the dark ever since.

"But you've surely slept since then?" Hermione said, absentmindedly slipping her hand down Charlie's arm until she was holding his fingers.

Charlie nodded and winced simultaneously. He wanted to be honest but that would mean revealing more than Hermione might be comfortable with. "Let's just say I don't have a problem sleeping if I have company in my bed. It's only when I'm on my own..."

Now it was Hermione's turn to be grateful that the fire's heat hid her own blushes. She knew of Charlie's reputation as a wizard who loved being with women from the odd comment that his brothers had made but it wasn't exactly something that she had planned to converse with him about.

She decided to stick to her line of questioning, although the tone of her voice was gentle. "You must have known you'd be sleeping alone here? And you seemed OK our first evening; you were looking forward to your new role. What's changed?"

"I thought the job would be good for me. Get me closer to Mum and Dad and the others." Charlie jerked his thumb towards the hut. "I knew I might not be able to sleep alone at night but I thought if I asked Minerva for the hut then I could sit out by the fire and then catch up during the day and at weekends; that's how I managed after the war." He swigged more beer.

"Is that not working, though?" Stupid question, she thought. It couldn't possibly be working; he wouldn't look so tired if he was, but she seemed to need to carefully tease each bit of the story from him.

Charlie shook his head slowly. "My schedule is heavier than I thought and I'm only getting two or three hours in between dawn and when lessons start."

"Oh Charlie..."

"I don't want your pity," he said, rather sharply.

"Good, because you're not getting it," Hermione told him. "But why do you think I'm here?"

"I don't need a bloody babysitter," he said. "Some things a man needs to figure out by himself."

"Bollocks!" Hermione replied.

"Beg pardon?"

"I said that's bollocks, Charlie. We've already discussed this. Do you think you're the only one affected?"

"Fuck, no." He was a tad worried now that she thought he was being selfish.

"We all need to help each other." Hermione was firm.

"I still don't need a babysitter," he repeated.

"Of course you don't. And frankly, you can be as grumpy with me as you like, Charlie Weasley. But there a simple solution here, which will help me as well, and I cannot look your mother in the eye on Sunday knowing that I left you in this state when I could have helped us both. Come on!" She took his hand and led him towards his hut.

Charlie was so stunned by her straightforward, bossy approach that he simply obeyed. That was another Weasley male trait that Hermione rather appreciated. Charlie allowed her to lead him to his cabin as she muttered a lumos spell and watched him do the same. Leaving him outside in the light for a moment, she entered his space and summoned a number of clear glass jars from a cupboard.

"How did you know they were there...?" Charlie began, as he stood just outside the door, and then remembered how much time she had spent here with Hagrid during her own school years. He watched, fascinated, as she cast spells which added glowing blue lights to each jar, levitating them to hang around the walls and ceiling that were next to the quilt-covered bed so that they added a subtle and comforting illumination to the wooden cabin. "That's amazing," he said, quite forgetting to be grumpy for a moment.

"Come on then," Hermione said again, as she waved her wand to put his outside lights out and ensure that the campfire was safe. Holding out her hand, she encouraged Charlie into the nightlight-filled cabin, led him to the large bed in the corner and finally whispered 'nox' to her wand now that the space was lit to their mutual satisfaction. "Which side do you like?"

Charlie pointed to the nearest side. He had figured out Hermione's plan and he was buggered if he was going to let this little witch sleep nearest to the door. Scared of the dark or not, he still had an urge to protect her by laying himself between her and any possible danger.

With little ceremony, Hermione slipped her outer robes from her shoulders and let them slip to the floor while she toed her boots off. She climbed onto the bed - which was higher than she had realised, making Charlie chuckle a little - and slid herself under the covers.

"Come ON, Charlie, I'm cold!" Hermione smiled at him. It had occurred to her that stressing her own needs might be the key to making this more acceptable for him. "You think I'm doing this just for you? Well, I'm not that altruistic. I've been bloody freezing since the war and I don't sleep well either because of it. That's why I have George's sweater, remember? So this isn't just about helping you. You'd be doing me a massive favour if you'd just lay next to me and warm me up enough to sleep. I'd get a big dog to snuggle, but Crookshanks wouldn't be happy and you smell better..."

Appeased - although not stupid - Charlie decided he could go along with this, if only to get one good night's sleep. He shed his own outer clothes, climbed in beside Hermione and put his arms around her. Hermione shifted a little, so that Charlie was spooning her, and she pillowed her head on one of her hands and tangled the fingers of the other together with Charlie's.

"Happy now?" he asked, still a bit gruff.

"Very happy, thank you. And much warmer. Night night, Charlie."

Despite himself and the fact that it wasn't even that late, seven minutes later, Charlie Weasley fell asleep, calmed and comforted by the soft blue glow of Hermione's nightlights and the even softer company of his friend. It was the best sleep he'd had since arriving at Hogwarts and he didn't wake until their wands softly vibrated in the morning.