Harry looked around in wild panic. What was he supposed to do? Where was he to hide? But there was no place to hide and Sirius was steering directly towards him, without the faintest gleam of suspicion on his face.
The corridor was dark. Not completely - Sirius was still very visible against the big, arched windows that showed the Hogwarts grounds in the gloomy atmosphere of an early autumn evening, but dark enough for Sirius to squint his eyes slightly until he was standing right in front of Harry, grinning broadly down to him.
'There you are,' he said, his voice cutting though the silence of the deserted corridor like a knife, although sounding quite pleasantly. 'I've been looking for you. Guess what? He actually went after him.'
Harry stared up at Sirius, pain rising in his throat again, as much as a sudden, irresistible urge to embrace Sirius - his godfather, whom he had missed so dearly over the summer and during his first weeks back at school. And here he was, standing, talking to Harry as if they had already met. As if they had been friends before - in another life. Another time. Harry closed his eyes for a moment.
'What do you mean?' he finally managed to say. 'Who went after whom?'
'Why, Snivellus, of course,' said Sirius impatiently. 'He went after Remus, just a minute ago. I told him some crap about hidden quarters and he actually believed it!' He gave his characteristic bark of laughter and Harry's stomach cramped. This was not his Sirius. Well, it was, technically, but he seemed... different from the person Harry had once known. Wilder. Less concerned.
'Where did Lup- Remus go?' said Harry in a low voice, taking care now, not to step into the light, as he knew his green eyes would give away him at an instant. 'And why did Snape follow him?'
'Really, mate,' Sirius frowned. 'You been listening at all? Remus went off to the Shrieking Shack! It's his time, remember? And if you hadn't been busy smooching that Ravenclaw chick, we wouldn't have missed the opportunity to join him.'
Harry's heart sank. He suddenly remembered that this might well be the time - the night - in which his father had gone after Snape to pull him out of the tunnel leading to the Shrieking Shack. In fact, Harry gulped, there was no way James would do that tonight. Would be able do it. He was up in the North Tower. There was no way he was going to get down in time.
It happened in a fraction of a second. Harry slammed down the library books Madame Pince had shoved into his hands earlier and started towards the entrance, without taking another look at his godfather's younger self, but suddenly stopped, as a nasty thought had appeared in his mind and stopped his - how had Hermione put it? - "saving-people thing" in the middle of taking control over his actions.
What if - he did not go? What if he let Snape reach the Shrieking Shack and meet the fully-grown werewolf Lupin was bound to be by now?
But Harry knew that he could not do that. That Lupin would not recover from having killed a fellow student - that Sirius would get expelled and that he, Harry, would not have travelled back in time in the first place, had it not been for Snape.
He reached the Whomping Willow within two minutes. Jumped into the black hole under its unmoving branches and roots and ran through the blackness of the corridor as if his life depended on it - which it did. He was gasping for breath by now, not failing to notice that the air of the corridor had assumed the unmistakable odour of a certain office Harry had come to dread during his Occlumency lessons. Snape had to be near.
Sure enough, the future Potions master's bony outlines became visible shortly before he had reached the last turn.
'Stop!' Harry panted, grabbing the figure's lank shoulder. 'Don't go any further!'
Snape stopped He turned and looked straight into Harry's eyes. A strange gleam appeared at his face.
'Potter,' he said slowly, putting emphasis on every syllable, 'what are you doing here?'
'Don't follow him, 'Harry said breathlessly. 'He's turning into a werewolf!'
Snape smirked. His eyes were resting on Harry's face, but he did not seem to have noticed anything.
'Black told me quite a different story,' he said gleefully. 'He told me Lupin was checking on your secret hideout. Making sure everything was ready for your next... 'practical joke'. And, quite frankly, I am prepared to believe him for a chan-'
He stopped. There was a growl coming from behind the corner. A deep and dangerous growl. Harry froze as well and took a sharp breath. The growling drew nearer.
'We've got to leave,' whispered Harry. 'Quickly!'
But Snape was not moving. His eyes were fixed on a spot behind Harry, and slowly, carefully, Harry turned in that direction.
What he saw made his insides cramp. Behind him, emerging from the shadows like a massive omen of death, stood the werewolf, his gleaming yellow eyes fixed at the two boys as if deciding which one to leap at first. Harry made an unintentional step backwards. Technically, Lupin looked like a normal wolf. He had seen him before - during his first encounter with a journey through time, but from a closer distance, Harry found that the difference between the two species was a considerable one. Especially considering size and potential danger. Snape, apparently, was of the same mind.
'Run,' whispered Harry, knowing that it would be no good, but seizing Snape's collar and dragging him back into the opposite direction of the tunnel.
Lupin growled (was it actually a bark of laughter?), jumped, and was suddenly before them again. Harry stopped dead. In wild panic, he turned around and leapt around the corner towards the entrance of the Shrieking Shack, closely followed by Snape this time, but he suddenly remembered that an escape through the racked doors of the Shack would not very well be possible. He whirled around, determined to find a way out of the situation and suddenly noticed that Snape had stopped, gasped, and was searching the pockets of his robes in what seemed to be total calm now. He withdrew a phial, took out his wand and opened it with a plop.
'Help me,' he snarled. 'Make yourself useful. If we can force this down that beast's throat, we'll be safe.'
'I am not poisoning Lupin!' protested Harry and was surprised to see Snape smile distinctly.
'No,' he said slowly. 'It won't harm him. I promise it won't.'
'What's your word worth?' spat Harry. 'You're -' He stopped. Was it any good to inform Snape that he was about to join the Dark Lord's inner circle? Probably not. He shut his mouth again. Snape sneered.
'As much as Black's. But you don't have a choice. It's him or us.'
And with any further delay, he turned round the corner, seizing the phial in his fist as he did, facing the werewolf with every limp of his body shaking of determination and, Harry thought, madness. The wolf grinned and approached the small Slytherin on a snail's pace, ready to strike every moment.
'NOOO!'
Within seconds Harry had jumped forth, desperately pulling out his wand as he did, yelling the first spell that came into his mind: 'EXPECTO PATRONUM!'
The werewolf staggered. The patronus affected him ever so slightly, but this split of a second was enough for Snape to jump forward and pour the steaming liquid down the animal's throat. Harry gasped. The werewolf howled and Snape backed away from him, his eyes wide open, as if expecting a huge blow to fall.
Lupin coughed, howled again and - closed his mouth with a snap. Harry opened his eyes again. Was it just him or had the wolf's snout shrunk just a bit? Snape was staring, open-mouthed, in the same general direction, obviously realizing only now what he had done. Harry grinned.
'You should have been in Gryffindor,' he said, 'for what you just did. Was that Wolfbane Potion?'
Snape did not reply. He merely stared at Lupin, who was pacing around their feet now, trying to catch their attention or, perhaps, wanting to be caressed. Harry ignored him as much as possible, still not knowing the precise effect of the potion, whereas Snape did still neither move nor speak.
'Was that Wolfbane Potion?' Harry inquired again, suddenly very eager to know. 'Did you... did you invent it?'
Snape did not move. He was standing with his back turned at Harry, who hesitated for a moment but then approached the lanky figure of his Potions teacher's former self and placed a hand on his shoulder. Snape backed away. He turned and looked Harry in the eyes again, who realized that he had chosen an inopportune moment for opening up to the school's most hated individual. Snape was crying.
Harry lowered his hand and frowned. 'Now look,' he said helplessly, trying to get over the shock of seeing Snape in such an undignified situation, 'don't do that. It's over, you know.'
Snape wiped his face with his hands, spreading dirt all over his pale face and - Harry could not believe his eyes - raised his wand at him.
'You almost got me killed,' Snape said slowly in barely more than a whisper. 'You tried to murder me. All three of you!'
Harry stared at him. 'Now, see here,' he said urgently, not wanting to think of the fact that Snape's guess was probably rather accurate as far as Sirius and James were concerned. 'I went after you. I came to your rescue!'
But Snape was not listening. 'Periculo!' he yelled at the same time as Harry shouted: 'Expelliarmus!'
Harry's spell was more effective. Snape's wand was blasted from his hands and into Harry's own. Snape swore badly and leapt forward, but Harry shot a stunner directly at his chest. Snape's limps snapped against his body and he fell. The pacified werewolf, having tried to passionately nip Harry's robes, could only just get himself out of the way before Snape crashed on the muddy tunnel ground. Harry grinned.
'This is so ridiculous,' he muttered. 'Does this mean I'll be the one to get Snape out of here? That I did what my father was praised for all his life?' And with a wave of his wand he lifted Snape's stunned body and motioned him towards the entrance under the Whomping Willow.