“McGonagall,” Severus said shortly, nodding at her in appreciation as she handed a fidgeting Harry the last of his belongings. “I’m sure Mr. Potter is very appreciative.”

“Oh, um-er. Yes, thank-you, Professor.” The boy stammered, his nervous silence breaking at the reminder. The Transfigurations mistress gave Severus a questioning look that was tinged with worry, but brushed off Harry’s thanks with a wave of her hand.

“No need for that, Mr. Potter. I do not want to be the one responsible for one of my-” She cut herself off and settled for giving the boy an awkward and sad smile as her colleague turned towards the office door. “Well…Have a good evening then, Mr. Potter. And you as well, Severus.”

Opening the door, he granted her another nod before ushering his newest Snake out into the corridor and closing behind them. “Mr. Potter, there are things we must discuss. Take your things to wherever you’ve managed to hole yourself up these past weeks and report to my office at half-past-nine. I’m certain you know where it is located?”

The still stunned boy looked up at him with a blank expression, but nodded before starting off down the corridor away from what Severus privately called Lion territory.

You hide so much beneath that blank face, my son. I wish to know you, wish to correct my wrongs. Will you let me? Severus shook himself and checked the Muggle watch he had managed to smuggle past the castles anti-Muggle wards. It was so much more useful than the overly complicated and illogically designed wizard timepieces. He’d given the boy nearly an hour; hopefully, the time taken to put his things away would allow the change in his situation to sink in. That was really the only reason he’d sent the boy off. He himself had no particular task requiring the delay. Musing he located a vial of calming draught in one of his robe’s many hidden pockets, and spent a few moments examining the liquid in the flickering torchlight. Both he and Harry would likely need a dose before the night was through. As much as he disliked the idea of opening himself up to the upcoming emotional ordeal, he knew that keeping his shields up would only be harmful. The draught would help keep things at a safe remove until both of them had time to deal with events. He tucked the vial away; perhaps he should get a second one from his stores, just in case the boy was more distraught than he thought.

Of course, the boy is distraught. No child wants to learn that his least favourite professor is, in fact, his father, a voice in the back of his mind sneered.

And how would you know? he snarled back at himself without thinking. He found himself waiting for a response but none came. Pinching the bridge of his nose in aggravation—he wasn’t sure if it was towards himself, the boy, or just the situation in general—he closed his eyes and sighed before striding off in the direction of his office. It would not do for his son to arrive at his office to find him not there.

Carefully extinguishing the flame from under the small cauldron that sat on the workbench at one side of his office, Severus kept a wary eye on his son. Harry waited in the corner nearest the door as if torn between the need to protect his back and the desire to flee. His nervousness was obvious from the way his fingers plucked at the fraying hem of his jumper. Only minutes had passed since the child had arrived and it was clear that the boy was convinced that he was either going to be potions ingredients in a short time or Severus had some other dire fate in store for him. Though if the looks that he was giving the resting potion were anything to go by, it appeared that Harry seemed to have an idea of what it was.

“Harry,” the boy jumped in surprise at hearing his given name come from his Potions Professor’s lips and the green eyes darted a glance at Severus before returning his gaze to the cauldron, only to send it back to the man obviously wishing to ask what it was. “You may not want to believe that what you are about to learn is true.” He ladled out a portion of the cauldron’s contents into a dosing cup, the colour shifting, just as it ought when it touched the glass. Hell, I’m not even sure if what I suspect is true. I don’t really want to be doing this but— he forcibly stopped this train of thought and turned his attention back towards his son, whose gaze had once more settled on the potion and gestured for the boy to come forward from the corner where he lurked.

“Can you tell me what this potion is?” he snapped out, his nerves getting the better of his intention to make this as easy as possible.

Hands now stuffed into his pockets, and green eyes locked on the vial in Severus’ hand, Harry frowned as he hesitantly approached the workbench. Severus waited patiently as the boy examined the vial’s contents.

“It’s the Paternitas potion, isn’t it? Sort of like a Muggle paternity test, only it’s never incorrect.” The boy seemed even more wary now, chewing his lower lip for a few moments before adding, “It also tells the names of the parents to the child being tested.”

“Correct.” Severus attempted to hide his grimace and his surprise that Harry had correctly identified the rarely made potion. Why had he ever thought the boy was a dunce in his class? It was all his fault after all, no child did well under constant scrutiny. “However, at present the potion is inactive. I assume that since you correctly identified it, that you know what the activation catalyst is?” You are aware of the last ingredient then?”

Harry didn’t speak but held out his left hand palm up and fingers extended in answer. Either the boy was ready to accept what the potion would divulge, or the calming draught Severus had given him the moment he’d arrived in the office had finally taken hold.

Picking up the slender silver knife that sat on a piece of green silk to the side of the cauldron, Severus guided the boy’s finger tips over the mouth of the waiting vial. It was only a moment’s work to prick the boy’s forefinger and guide the resulting drop of blood into the thickening, grey potion. The potion immediately changed to a deep rich red, the single carmine drop staining the liquid in seconds. He held his breath as a silvery haze rose from the surface of the potion and wafted towards Harry. Wrought with both fear and some dread , he held his breath as the haze wreathed the boy’s head and the potion whispered Harry’s true parentage into his ears in the otherwise silent room.