Severus Snape went to his office and quickly took out several of the unbreakable crystal vials he had confiscated from Harry Potter. He took his time and put copies of his memories into them, to make sure he had them before visiting a powerful wizard like Dumbledore, just as he did when he visited Voldemort. It was insurance that he couldn't be obliviated, where he was given false memories or had them removed altogether. It also protected the memories that he wanted to keep safe.
When he was done, he strode across the castle to Dumbledore's office and said the password. The door opened and he rode the stairway up to the office. It was an ingenious delay mechanism that was designed to give him a head's up if anyone was trying to get into his office. The extra time also served as a buffer to hide away anything that Dumbledore was working on.
Snape's request to have a similar mechanism installed for his office was politely and firmly refused.
The door to Dumbledore's office opened and Snape calmly walked in, not revealing his urgency to confront the old man about all of his deceptions. It wasn't the denials he spouted about being ignorant of Harry's disposition and home life that were annoying. Those he could accept as justification to shift blame.
It was the cover-up about Voldemort being hired as a professor that irked him. The Dark Lord must have been very close to regaining a body of his own with Quirrell helping him and he almost had unrestricted access to the school. As a professor, he could walk the halls unimpeded and unmolested. That alone was terrifying for the wizarding world, let alone for one Severus Snape. He had no desire to search out the Dark Lord or to resume his former position as spy.
Snape stood there beside Dumbledore's desk and waited patiently for the old man to finish ignoring him.
*
Dumbledore sat there and pretended to ignore the potions professor to try and gauge the man's reaction to whatever news he had dug up. Unfortunately, he couldn't get a read on him. He was a spy after all, so that was understandable. It would be difficult to be effective if everyone could tell how you were feeling and guess if anything was bothering you. He tried for another moment to read him and then gave up.
“I have a feeling you are not going to tell me good news.” Dumbledore said and looked at him.
“If by good news, you mean that he wasn't verbally abused his entire life and beaten to a pulp every day by his cousin... that was three times his size... then no. It's not good news.” Snape said in as sarcastic of a tone as he could muster, which was a significant amount.
Dumbledore winced at the tone. “Severus, I'm sure that it wasn't that bad.”
“See it for yourself.” Snape said and placed one of the vials on Dumbledore's desk. “It's all there. Years and years of abuse.”
Dumbledore didn't pick it up.
“So, you knew.” Snape said.
“I suspected.” Dumbledore corrected. “Petunia wasn't fond of her sister; but, she accepted the boy into her home...”
“...because you paid her.” Snape said, then his mask slipped and showed anger for a moment. “Or, more correctly, Harry Potter paid her.”
Dumbledore didn't react or deny it, which meant it was true.
“Did you know that they didn't spend a single bronze knut on the boy?” Snape asked and Dumbledore still didn't react.
“Ah, I see.” Snape said with a bit of a sneer. “You 'suspected' and kept it to yourself.”
“I needed to keep the boy ignorant.” Dumbledore said. “I couldn't interfere with how he was raised.”
“No, you didn't want to interfere.” Snape corrected. “If he wasn't desperate to get out of there, he wouldn't have accepted being a wizard so easily, correct?”
Dumbledore smiled slightly and nodded.
“Is that also why he can accept killing a man so easily?” Snape asked.
Dumbledore closed his mouth and the smile disappeared.
“Yes, I found out.” Snape said. “Quite easily, I might add.”
“How?” Dumbledore asked.
“Obviously, whatever spell you used or false memories you implanted didn't take.” Snape said and Dumbledore looked uneasy. “Were there too many witnesses? Not enough time to cover up all of the evidence?”
Dumbledore sighed. “I was too late to catch the Aurors before they took Quirrell's ashes away.”
Snape had to smile. “Tom told everyone that came through the bar the same story, for the entire day.” His smile faded. “Only one coming back and telling him would undo everything.”
“Plus the Aurors getting statements and testimony at the Ministry.” Dumbledore said. “I'm just glad that they didn't charge Harry with murder.”
“They didn't have the evidence.” Snape said. “They dismissed it as an allergic reaction.”
“Tom told you that?” Dumbledore asked and Snape raised his eyebrows at him. “Yes, I'm sorry to doubt you.”
“Doubting me I can handle.” Snape said and glared at him. “Trusting me is another.”
“What do you mean?” Dumbledore asked, innocently.
“The gentle grandfather facade doesn't work on me, Dumbledore.” Snape said. “You know perfectly well what I mean.”
Dumbledore took a deep breath and let it out. “Voldemort.”
“Yes.” Snape said. “Did you really think I wouldn't discover that he was inside of Quirrell?”
“I thought I erased that memory.” Dumbledore whispered.
“You would have been better off altering it and not leaving a hole for his brain to fill in.” Snape said. “It was nearly intact by the time I talked to him. The other people around us recounting it filled in all the little details for him.”
“Indeed.” Snape said. “You are getting old and forgetful.”
Dumbledore gave him a stern look for a moment. “What would you suggest I do about it?”
“Now? Nothing.” Snape said. “If you had done something as soon as Hagrid came to see you, you could have saved the world by eliminating Voldemort, once and for all.”
Dumbledore couldn't steel his face in time to avoid showing that he knew something. Snape stared at him and didn't speak for several minutes. The two of them battled, mind to mind, and neither of them were willing to lose or give up. When they reached the five minute mark, they were both sweating and strain showed on their faces.
“Enough.” Snape said and looked away.
In that brief moment, Dumbledore saw that Snape didn't trust him any longer. To keep such deep secrets from him, secrets that were essential for Snape to function safely, made all the good will that he had built up over the years, mean less than nothing. What was the use of good will with Dumbledore if Snape was going to be exposed to The Dark Lord unknowingly?
“You weren't going to tell me at all that he was inside Quirrell.” Snape said, sure of that answer.
Dumbledore sighed. “No. You didn't need to know.”
“I didn't need to know... that The Dark Lord, whom I have been bound to... was possessing a man that was going to teach at the school.”
“The less people that knew, the better.” Dumbledore said.
“Less, meaning just you.” Snape said.
“It is the safest way to keep a secret.” Dumbledore responded.
“What were you going to do with...”
“It doesn't matter.” Dumbledore said. “All my plans had to change when Quirrell died.”
“To what?” Snape asked and Dumbledore didn't say anything. “Did those plans involve Peter Pettegrew?”
Dumbledore looked shocked for a second, then he sighed again. “How long have you known?”
“Since Missus Norris walked by my office with a giant rat in her mouth.” Snape said. “No secrets can be kept from The Dark Lord by someone so weak. Long has he known of Pettegrew's animagus state.”
“Did anyone else...” Dumbledore started to ask.
“Obviously, his 'friends' would know as well.” Snape almost spat. “They trusted him, didn't they?”
Dumbledore couldn't really respond, because they did and it had cost James Potter and his wife their lives. Peter had betrayed them and told Voldemort where the Potters lived.
Snape took a breath and let his calm mask overtake his emotions. “What are you going to do now?”
Dumbledore thought about not answering as he debated his revised plans. “If I tell you this, you must promise to do all that you can to help.”
Snape glared at him and he smiled.
“Yes, all right. I'm sorry that I've kept you in the dark about some things. Please, forgive me.” Dumbledore said and Snape stopped glaring. “It was for your own safety.”
Snape folded his arms into his cloak and waited. He knew he would play that card.
“As I see it, Harry and Voldemort need to meet in a few years...”
“They've already met.” Snape said, unnecessarily.
“Yes, and it went very poorly. Harry didn't face any trials, investigated any mysteries, or gained an interest in Defense Against the Dark Arts.”
Snape stood there and did his best to not glare again. “You... intended to have them meet... as Harry and Professor Quirrell.”
“Yes, after grooming Harry along to the appropriate paths to reach the right solution.” Dumbledore said.
“The very stupid security we were trying to set up on the third floor?” Snape asked and Dumbledore nodded. “What was it he was supposed to gain?”
“The Philosopher's Stone.” Albus said. “It was entrusted to me by...”
“I do not need a lecture.” Snape said. “How would you let Voldemort know that you had...” He stopped talking. “That's why you hired the idiot Quirrell. You were just going to bring it up and let it slip into a conversation for him to hear, weren't you?”
Dumbledore smiled. “I already did that. I made sure that he overheard when I told Hagrid to retrieve it from vault seven hundred and thirteen at the bank.”
“Then he died.” Snape said.
“Unfortunately.” Dumbledore said. “He was supposed to keep looking for it here at the school.”
Snape stood there for a full minute as he waited for Dumbledore to continue, then he spoke. “If you didn't need Quirrell to try and steal it and the plans to set up the third floor as a test for Potter fell through, then where is the stone?”
Dumbledore opened his mouth to say that Hagrid had given it to him, then remembered that all that happened that day was a blubbering and very upset Hagrid had informed him about what happened with Quirrell, then Dumbledore waited to get the witnesses alone to try and deal with the fallout.
Hagrid hadn't handed over the philosopher's stone.
“Hagrid.” Dumbledore said and stood, then he quickly strode across the office. “I need to see Hagrid right away.”
Snape watched the man leave in a rush and didn't follow him. Dumbledore left a spy inside his office, one that he didn't actually trust, and was all alone inside his inner sanctum. Snape smiled and waved his wand, put all of the portraits to sleep to stop their prying eyes, then got to work. He had dirt to dig up and he didn't have a lot of time to find it.