By the time Robin swung open the door of the office with its familiar frosted glass, she wasn't sure she had it in her to even make it to her desk, let alone begin the pile of paperwork that she had promised herself she'd catch up on tonight. Instead, she collapsed bonelessly onto the leather couch, letting her handbag fall on the floor beside her, closing her eyes and leaning her pounding head against the backrest.

"Are you okay?"

Robin cracked open one of her eyes and rolled her head to look at Strike, leaning against the door frame of the inner office. "Why do you ask?"

"You're wearing two different shoes," he said, and when she stared at him blankly he raised his eyebrows and looked pointedly at her feet. She followed his gaze, and it took a moment for her brain, fogged with exhaustion, to recognize that he was right.

"Of course I am," she sighed. It had been that kind of day. Waking up late to a mobile that hadn't charged; a missed bus, a spilled coffee, a day of exhausting surveillance with nothing to show for it. Now, as the rotten cherry on a shit sundae, she realized that she had just spent seven hours trailing her mark through pretty, high-class Chelsea in glaringly mismatched trainers.

She felt tears begin to well up in her eyes and closed them again, not wanting Strike to see her reduced to weeping over something so ridiculous. Mercifully, she heard him retreat into his office, and then the familiar sound of him rummaging through a drawer; but it was only a momentary reprieve, as his heavy, slightly uneven steps signalled his return.

"Here."

She felt him put something beside her on the sofa, and move away. A clatter in the kitchenette, the familiar sound of the kettle being filled and mugs being taken out of the cupboard; his back would be turned. She opened her eyes, swiping quickly at the stubborn tears, and looked down.

Beside her was a box of tissues – an essential for their office, in which so often the business of the day was to break bad news to disappointed spouses - but there was something else as well.

"What's this?" she said, picking it up; but she didn't really need to ask. She recognized the incredibly expensive brand of chocolates in their rich blue box, a thin glittering ribbon of silver knotted around it. She had purchased a small assortment as a birthday treat for herself half a year earlier, and had managed to stretch them out for a whole month.

"It's for you," Strike said gruffly, still fussing with the tea.

"No, it isn't," she said, staring at the box in bewilderment. There was no occasion coming up for which he would buy her a present; why had he had these in his office? It took a minute of thought, but then she had it. "It's Lucy's birthday on Saturday. These are meant to be hers."

Strike sighed inwardly to himself. Of course she had remembered.

"I'll figure something else out for Lucy," he said as he turned back to her, two fresh mugs of tea in hand. "Go on, have some."

"I couldn't," she choked out, tears beginning to roll down her face in earnest now, splashing on the lid of the chocolates that she held in her lap.

Strike set their tea down on her desk, and reached down to take the chocolates out of her unresisting hands. It was the work of only a moment to undo the ribbon and crack open the lid as she watched, sniffling.

"No choice now," he said, as he took a chocolate at random and popped it into his mouth.

It was nougat. Well, since he would willingly throw himself on a grenade for this woman, he supposed he could suffer through a piece of nougat so that she didn't have to. He offered the open box to Robin again, and she gave in, taking a piece for herself with a watery attempt at a smile.

"I've got a bottle of wine that I was planning on bringing to Lucy's too," he said, and then, mouth twisting to hide his smirk, "what d'you say? We could kick off our shoes, make an evening of it."

She half-sobbed, half-laughed at this, and nodded; he took her hand and tugged, pulling her up off the sofa to stand in front of him. Her face was quite suddenly just a few inches away, looking up at him, her eyes red and puffy but shining with more than tears. He hadn't dropped her hand, warm and soft in his.

"Thanks, Cormoran," she whispered.

He cleared his throat and stepped back. "That's what partners are for," he said, hoping that she wouldn't notice the sudden hoarseness of his voice. Had he imagined the sudden flash of disappointment in her eyes? He must have, because she was smiling up at him now, and his heart hammered in his chest at the thought that the crinkles appearing at the corner of her blue eyes and the soft fondness that suffused her face was all for him.

"Partners," she affirmed, ignoring the tingling warmth that had spread up her arm at the touch of his hand on hers.