Disclaimer: If I were the author of Harry Potter, I would be using my money to travel the world writing original works at my leisure instead of writing fan fiction in hurried snatches in an obscure corner of the globe.
She still remembered the first time he noticed her. Later he would say that it was not the first time by far, but she was never sure if she believed him. In any case, that was the first time Hermione became aware of his noticing her, and therefore she recalled it as the turning point in their relationship.
She had changed into the clothing required for the assignment. The outfit was nothing special, just a tool to project the required image of elegant professionalism. Black pencil skirt, matching heels, a merlot silk blouse, hair smoothed back into a French twist, a string of pearls at her throat. After months of living in survival mode, it felt good to put on something feminine and pay attention to her appearance. Though the outfit was just that of a typical female office worker, it helped her to remember for a moment that she was a woman and not only one unit in a group struggling to fight and survive. She lifted her shoulders with confidence and dabbed on just a bit of perfume before folding away the self-remembrance and turning her mind to the task at hand. She left the room and firmly closed the door, promising herself that if - when - she survived, she would open the room again and explore the selfhood that she had remembered there. But for the sake of all that was important to her, she must remain simply a member of the faction for now. If individuality emerged, the cohesiveness of the unit would be broken, and their cause would be jeopardised.
He was waiting for her in the foyer between the rooms of their suite. She didn't look at him as she crossed the room to the coat rack where she had hung her robe. Not facing him was childish, she knew, but she could only handle so much. She would have to deal with him enough in the next few hours. As she settled the soft black robe over her shoulders, her mind flitted to the mission ahead. Logistics, spells, and strategy flooded her thoughts. Had she forgotten anything? Her mind ran down the checklist. No, she had everything. The question was, had he forgotten anything? She turned her head to look at him and asked, "Did you owl-?" Her question was half-finished when she realised he looked strange. She stopped speaking and turned fully to study him.
It was his jaw. His mouth was relaxed. That was what had struck her as different about him. For months now, ever since he had joined them, he had walked around with his jaw clenched and his neck muscles strained. Those were the only two signs she had, ever, that Blaise Zabini was under any pressure. Not that she had ever gotten closer to find more. It was hard to accept that the pampered Slytherin acquaintance of Malfoy's was now one of them, and though he and she were always distantly polite to one another, she remained wary. She hadn't been exactly thrilled to realise that so much rested on his trustworthy cooperation, nor that he had been chosen to go with her alone and help carry out the mission. And now he was behaving uncharacteristically, which could potentially mean trouble for her.
Hermione analysed him carefully. His jaw had tipped her off, but there was something different about his whole expression. It was the way his entire face was unguarded, as she noticed now that she was paying attention. His mask had slipped. And in that brief moment she had a glimpse of what he was feeling. He looked a bit dazed, as if he had just apparated into the middle of Lisbon when he had expected to end up in a sheep pasture in Yorkshire. His eyes had softened, but they also looked greedy - hungry, like he was looking at chests of gold or the deed to a sprawling estate in Ravenna or whatever it was that interested a Zabini. She couldn't claim to know. But mostly he looked surprised and confused. And suddenly the mask slipped back into place, the eyes steeled, the jaw clenched. The moment was over before she could process it.
"The Order to let them know we've arrived?" he finished her question. She had almost forgotten she had asked something and had to stop to recall what it had been. He went on haughtily. "Of course I did. I know it's difficult when you haven't had better company, but try to come to terms with the idea that not everyone is as incompetent as those pea-brained louts you call your friends."
She bristled and almost rose to the bait. Almost. That was the longest insult he had spared her since he had joined the Order, and it didn't zing sharply like the ones she had heard him use before. He was trying too hard. It was cover. He knew she had noticed something different about him, and he was trying to throw her off the trail. This ability to quickly pick up on tiny details and string them together to reveal valuable information was perhaps the skill she had honed most during the conflict. The war had forced her to survive by it. It had served her well until now, so she would continue to rely on it. And now it told her that he was hedging. So she only said, with a calm voice, "Good." Inside she returned to the mental path her thoughts had been taking before his mask reappeared. What had caused him to react that way? Any information she could glean about him would be valuable, especially if he was trying to hide it. What had he been looking at, anyway? When she had been looking at him, she had had the feeling that he was looking at her, but that couldn't be right. She glanced behind her. The only things there were the coat rack, the wall, and a small table with a vase of fresh bellflowers on it. Nothing noteworthy. She couldn't puzzle it out.
He was still watching her. "Are you ready?" he finally asked, each word packed with as much scorn as possible. She gave up, for the moment. There was nothing there to look at. He was strange and she didn't understand him. She would work on the mystery later. Now there was work to do. "Yes, actually," she answered evenly. She did not want to fight with him, today of all days. She did not even want to go with him, but she trusted her friends and loved her cause, and both asked her to do this. She pulled the bottle of Polyjuice Potion from her robe pocket as he lifted one from his. Staring each other down, they uncorked their bottles and drank. As the familiar, sickening potion entered her mouth, Hermione promised herself she would make this mission successful if it killed her. Or him. And she meant that in the most literal sense.