It was one o'clock in the morning and, in Dumbledore's study, Snape was on the brink of total collapse. He had made such excellent progress at the beginning! After years spent hiding his emotions and guarding his thoughts, he had become very adept at suppressing fear, anger, uncertainty, guilt – emotions that would immediately draw the Dark Lord's attention to his disloyalty. He had emptied his mind of negative thoughts, he had, he thought, attained calmness and self-control. But it seemed that this was not enough. Again and again, Dumbledore accessed half-buried memories from every chapter of Snape's life, being deliberately unsubtle so that Snape would be in no doubt that his defences had been broken. He felt as though he had spent the last few hours reliving all the worst moments of his life – events he would never have recollected if Dumbledore had not pulled them out and forced them to the front of his mind. He was staggering now, unable to cope with the confusion of images that were crowding his mind.
"Some fresh air might be in order," said Dumbledore, looking concerned. He crossed the room and opened one of the windows.
The door, which had been left ajar so that they would hear any unexpected visitors climbing the spiral staircase, suddenly blew open as wide as it could and then slammed shut with an almighty crash. Several of the sleeping portraits woke up, startled by the noise, and then, as Dumbledore nodded very slightly, immediately closed their eyes and began to snore tactfully. Snape saw none of this unspoken exchange, however – the slamming door had given him an idea. As he once again tried to clear his mind of unhelpful emotions, he started to picture a building with many rooms and doors – and he methodically began to close them all. This was it! He could seal all of his most incriminating thoughts safely out of reach of the Dark Lord – he could lock the doors. As the last door closed, Snape turned to Dumbledore and said, "Again. Try again." He took a deep breath and waited.
Seconds later Snape was once more reeling under a barrage of random memories. It hadn't worked! What was he supposed to do? He felt like giving up. But – mastering occlumency was his only chance for survival. He was going to have to try again, but not yet. To buy himself a little more time, Snape went to the open window and breathed in the cold, damp air.
Dumbledore sighed. "Closing doors is not enough, Severus. Any capable Legilimens would instinctively try to open them – and there would be nothing you could do to stop that."
"Then it seems to me that nothing could stop a gifted Legilimens!" Snape spat. He was defeated. There was no hope.
"On the contrary, Severus – you're very close to succeeding. But you have to do more than simply seal off sections of your mind. It draws attention to the fact that you have something to hide." Dumbledore sat down at his desk, seemingly as exhausted as Snape. "An element of misdirection is needed as well. The contents of a human mind are generally very disordered, and any sign of organisation will consequently stand out."
Snape gazed blankly out onto the castle grounds. Dumbledore's words made sense – but how to go about it? In the dim light of the waning moon he could just make out the deeper shadow that was the Forbidden Forest. Perhaps if he pictured his mind as a forest, or flung a barricade of dense woodland infront of his building? But Dumbledore would hack down the forest, fight through the woodland, and there would be that building – an obvious target. No – that wasn't the solution either.
"I wish I could be more helpful," said Dumbledore, speaking slowly, as though he was choosing his words with great care, "but it is essential that you find your own style of defence. Occlumency and Legilimency are highly personal skills – no two wizards practise them in the same way. If I were to explain, step by step, exactly how to shield your mind and you consequently followed my instructions – what would happen? An artificial path would be created through your own thoughts – and that would lead any Legilimens straight to your concealed emotions and ideas. Do you understand, Severus?"
"Give me a moment," replied Snape. He was beginning to understand, finally, what he had to do. In his mind, the image of the building was wiped out by an unending forest, each tree a memory or thought. The suspect, dangerous ideas appeared no different from any other but the paths of the forest seemed, quite by chance, to avoid them. Would this work? He approached the front of Dumbledore's desk and, looking steadily into his eyes, said, "I'm ready now."
Nothing happened. If felt to Snape as though there was the ghost of a presence walking through his forest – but no memories engulfed his thoughts, and his darkest fears remained hidden. He looked questioningly at Dumbledore.
"Much better! Yes – you're almost there, Severus."
Almost? He had succeeded in blocking Dumbledore's attack! "But you didn't access my mind! What more do I have to do?" Snape could hear the despair creeping back into his own voice.
However, Dumbledore seemed quite amused. "Well, I would only observe that, as a rule, people do not tend to fill their minds with forests. Even though it worked, it looked rather suspicious. I have been a Legilimens for many years now, Severus, but I have never before visited a mind so beautifully and carefully depicted." As Dumbledore continued to speak, Snape sat down and massaged his aching head. "You have achieved a great deal tonight. Indeed, you have created a defence that would stop any Legilimens. However, we are trying to prevent Voldemort from accessing only certain parts of your mind. We are trying to hide from him any suggestion that you might be practising occlumency. I suggest you try to deal with the raw materials, rather than their appearance."
And this was the difficulty. Snape did not want to face his anxieties about the Dark Lord and the Death Eaters, the torture and death, the humiliation and pain, his own culpability. Not in front of Dumbledore. Although he had been through many nights of solitary anguish, he still did not feel ready to disclose that pain to Dumbledore – even if, through legilimency, he had now witnessed more of Snape's life than anyone else.
"I think, Severus," said Dumbledore, quietly, "that now might be a good time for you to answer that question."
"Question?" What was he talking about? The only question dominating Snape's thoughts at that moment was whether or not he was going to survive his next meeting with the Dark Lord.
"The question I asked several hours ago. What happened to you?"
Snape remained stubbornly silent.
"Come, Severus. It is time you saw yourself truly. Why did you become a Death Eater? And, more importantly, why did you come to me?