"Dobby?"
Harry thought better than to explain it all himself. If Snape wanted the whole story, it was better for him to hear it directly from the source. Actually, Harry wished he didn't have to listen to the whole thing a second time. The more he thought about it, the sicker he felt. Never mind that he'd thought a time or two about sneaking into the Slytherin common room and playing some sort of prank on them. He'd never have done anything like this.
When Dobby's story was over, Snape looked more thunderously angry than Harry had ever seen. Which was really saying something, considering how angry Snape had got at him over the years. His eyes were a seething black beneath eyebrows stretched into a taut, thin line, and his lips were white with rage.
"And no-one knows any of this save you?" he rapped out. He'd been pacing for a while by then, but when he asked the question he stopped, fists at his side, and gazed fiercely down at Dobby.
Dobby had seen too many furious wizards in his time to take one lightly. "N... n... no-one except Quilly, but she is not knowing anything except I took the fairy cakes away to be food-testing them."
"It's all right, Dobby," Harry said in a soothing voice. "He's not angry at you."
Snape shot Harry an annoyed glance but didn't contradict him. "And normally if you investigated an item and it contained no poison, you would...?"
"Dobby would put it back for d-- d-- delivery, s-- s-- sir..."
Snape lapsed into thought. "Will Quilly remark upon it if the tray never reappears?"
Dobby got an odd look on his face, though he managed to shake his head no.
"What, Dobby? What?"
Looking apologetic then, Dobby whispered, "Quilly will not be noticing. The Slytherin rooms, they is always such a horrible filthy mess, Harry Potter, that the house-elves... er..."
"The house-elves what?" Snape barked.
"The house-elves is taking turns cleaning there," yelped Dobby. "Quilly will not be back there for another month!"
"Fine," said Snape in a short voice. "Say nothing about this matter, elf. Nothing. Ever. Not even to Harry Potter." Pausing, the Potions Master appeared to give that some thought. "Harry, perhaps it would be best if you told him the same."
Harry knelt down, grateful that Snape hadn't suggested forcibly binding Dobby to some sort of silencing spell. Or worse, Obliviate. He was actually surprised his father hadn't suggested that, but perhaps it didn't work on elves. "This has to be our secret, Dobby," Harry told him. "It's important."
Dobby gulped. "I was already telling no-one because I knew it would hurt Harry Potter."
"I know." Harry gave Dobby a swift hug. "You're a good friend."
Dobby's big eyes shined with tears. "But Master Malfoy, Harry Potter. If he is getting away with this, he will be doing it again and again, Dobby is thinking. He will break Harry Potter's heart!"
"No," interrupted Snape, his tone of voice one Harry had never heard from him before. Hard, cold, and utterly merciless. "Draco won't do this again. Draco won't do anything like this, ever again."
"What are you going to do to him?"
Snape ignored Harry's question in favour of waving for Dobby to leave. Sighing, Harry handed Dobby the book back. Snape didn't need it, and Harry didn't want to dwell on the details of that particular poison any longer.
With a final mournful look at Harry, the elf at last Disapparated.
"What are you going to do to Draco?" repeated Harry. "What else can you do? You've already taken his wand--"
"My wand!" snapped Snape. "And as for what I plan to do, I'm still considering the matter. But one thing is certain. You will not interfere."
"Dad--"
"Do you want to see your brother sent to Azkaban?"
"But Dobby won't tell anybody--"
"No doubt. He's loyal to you, but he's also quite correct. Draco will indeed do this again--or something worse--unless he's stopped now. So answer me! Do you want to see your brother sent to Azkaban?"
"No, of course not!" Harry took a step back, the look on Snape's face more unnerving than he would have thought possible.
"Then do not interfere!" Snape assessed his expression, then waved his wand to levitate the tray of fairy cakes. Once it had floated into the Floo, the Potions Master reached for the ivory cup on his mantle. "We'll go talk to Draco, now."
"And tell him what?"
Snape gave Harry a thin, menacing smile. "Oh, I'm in no mood to tell your brother anything at present. Let's see what he has to tell us, shall we?"
With that, he pulled Harry into the Floo with him and threw down the powder that would send them both hurtling home.
------------------------------------------------------
The shower was running when Harry and Snape arrived, which Harry counted quite a good thing since it would give him a chance to talk with his father.
"Why'd you bring those along?" he said, shuddering.
Snape deftly waved the tray over to the dining room table. "What would you suggest I do, leave them in my office so that students wandering in can help themselves to a tasty treat?"
Harry blanched even though the suggestion was absurd. "Your office is warded and besides, nobody's going to come asking for Potions help when there are no classes for a week!"
"Regardless, I'm hardly disposed to leave them unsupervised."
Harry could appreciate that. "Can't you just banish them to nowhere?"
"Oh, certainly I can," Snape mocked. "I do believe I've known that spell for some years, Harry. But I think they can perhaps be put to better use here. The card, however..." It abruptly vanished under the force of Snape's spell, though Harry had a feeling it had only gone as far as his father's bedroom or office. As the shower stopped running, Snape lowered his voice. "Follow my lead."
Harry waited for his father to say more, but the man just stared at him, one eyebrow lifted in challenge.
Harry finally gave it up. "What are you planning?"
"I told you, I wish to hear what your brother has to say."
"What does that mean, you want to trick him into lying to you? What?"
"Perhaps you would have to be more fully Slytherin to understand," murmured Snape. Whatever else he had been going to say was lost as Harry's bedroom door swung open and Draco emerged.
"So, are we off to Devon then?" he at once suggested. "I'm already packed--"
"Alas, Harry is not," Snape said, shaking his head. "But no matter. Tomorrow will be soon enough to depart." He took a pinch of powder and tossed it at the grate. "Whatever suits each one of us, I should think."
As the elf in the fire nodded and whisked himself away, Snape turned towards the table.
Harry knew the exact moment when Draco saw what was waiting for him there. The other boy's step faltered, his mouth falling open. He recovered quickly enough, however, and sauntered forward as though he hadn't a care in the world. "Where did you get those, Severus?" he asked, glancing at the fairy cakes as though confused. "Oh, did you fetch them from the kitchens, Harry?"
As terrible a liar as ever, Harry thought.
"I brought them," Snape tossed out. And he, Harry thought, was definitely not a terrible liar.
All those years working as a double-agent...
"They'd been delivered to the Slytherin common room," Snape went on, his tone almost absent-minded by then. "But the state of the room lately has rivalled your bedroom for slovenliness. I hear the elves actually fight with one another to avoid Slytherin, so I rather thought the students didn't deserve such a lovely treat."