She straightened her legs and jumped from the sill she sat on. She glanced around. The dimly lit room was rather small. She found it by accident in her third year when she hurt her foot. She was looking for support and grabbed a sconce then almost toppled over when it moved under her hand. When the sconce moved, a part of the wall by it moved as well, revealing a small dark chamber. It was obviously unattended for quite some time (even by the house-elves) as layers of dust covered what little furniture was left.

It was a sort of a sitting room with a fireplace, two armchairs that were falling apart and a window that took up the whole of one wall. The window had a nice, big sill with a sort of a cushioned seat. The big window presented a magnificent view of the lake from beneath the surface. On the more sunny days, it gave the room a soft green lighting and on others covered the small space in darkness.

Throughout the two years that passed since she found it, Catharina managed to make the space her own. For the first few months, she had to go through a lot of trouble to properly furnish and secure the space. She placed all protective sigils and wards she knew (and that was a few) on the door, she went through some of the more advanced spell books and thought herself every spell to keep that place safe and used it. She also had to use the reducing spell on a few pieces of furniture she took from some abandoned classroom and move most of her belongings from the dormitory in a way that no one would notice. Not that anyone paid her much attention anymore, anyway. For most of her third year, she cleaned the room, repaired and transfigured what she could to make it more comfortable. During her summer, holidays that year she made her aunt buy her a nice trunk with an undetectable extension charm cast on it so that she could transport more things into Hogwarts. That allowed her to bring a small desk with her along with a bookshelf and a ton of books.

All the effort she put into arranging the place to her liking paid off as it became not only a quiet workspace but also a convenient hideout when she happened to run across the marauders once in a while or when she was being pestered by her housemates to join weird dark arts fan club they seemed to have. She did not even have to go to the library anymore as she brought most of her book with her in her fourth year and what she did not bring along she simply ordered with Flourish & Blotts in Diagon Alley and they owled it to her.

Now she straightened and stretched, feeling her muscles relax. She spent a few hours studying and now it was past curfew. She'll have to get back to her common room unnoticed or she'd be forced to sleep crouched uncomfortably on the armchairs. She put away her textbooks and put out the fire and the candles. Using her wand for illumination, she hurried to the makeshift door. The chamber was placed somewhere between the Slytherin common room and the entrance to the dungeons. It was the Slytherin turf and she was not likely to be hurt by her housemates, also at this time of the evening almost no student of the other houses would venture here.

She carefully applied all the wards back into place and slowly and cautiously she crept along the walls of the dungeons. She knew a few faster ways to get herself to her dormitory but it gave her a thrill to be skulking around school corridors unnoticed. She was almost half way through when she heard muffled sounds along with quiet giggles and chuckles. She carefully peeked from around the corner.

She saw two tall figures accompanied by a shorter one standing over a prone shiluette on the floor. The trio was visibly shaking and judging by the sounds they made they were having quite the fun. She recognised those three almost immediately. Black, Potter, and their sidekick Pettigrew. How dared they attack a fellow Slytherin this close to the common room? She boiled inside. The fury in her abated a little when she recognised their victim as her least favourite classmate – Severus Snape. He was gagged and was struggling in his bonds, quite to no avail.

She heard Potter whisper to his friends 'We should charm all of his hair off, maybe then he'll have less trouble keeping it clean' And the Gryffindors started laughing so hard Pettigrew almost choked. 'Quite the good idea, Prongs' Black whizzed out and when he could control himself a bit better he pulled out his wand and pointed it at Snape. The latter immediately stilled, his eyes trained on the wand. Instinctively she had her own wand drawn before she could think about what she was getting herself into. She sent a silent shield charm to protect Snape. The spell Black murmured rebounded and hit the caster instead. As Black lost his famous dark mane, his friend indulged in another laughing fit. No one noticed as she disillusioned herself and crept towards Snape. She released his bounds and noticed he was now completely still, his eyes wide. He noticed her. She bent over to his ear and whispered slightly. 'I'm going to disillusion and disarm Potter, ok? Be ready to run' She received a slight nod in return and straightened to put her words into action. Strengthening the shield between herself and the Gryphons, she removed the disillusionment.

The trio in front of her had no time to react as she pointed her wand at Potter and sent a silent disarming charm at him. As Potter hit the wall behind him, Snape caught his wand and disarmed Black before the latter had time to as much as breathe. The two Slytherins were left with their victims unconscious and a third boy standing there shivering. When they both turned his way he just squealed and fainted dead away. She wanted to run but saw Snape standing as if glued to the spot, breathing hard more in anger than exhaustion with murder written all over his face. He was raising his wand when she drew a sigil and summoned the banshee scream. The sound exploded all around them and Snape fell to the floor clutching his ears. When it was over he was on his feet and yelling at her 'Are you mad?' Her only response was 'We better run, the teachers will be here any moment.' And she was left with no other choice but to follow as he pushed against her and disappeared in an adjourning tunnel that led back towards the Great Hall. However, she kept back a little and muttered 'Enervate' as she turned to follow Snape.

As she did so, she heard hurried steps approaching through the main tunnel, moments latter she could hear a shrill scream of 'Potter! Black! Pettigrew! DETENTION!' . It was undoubtly professor McGonagall who got to the marauders first. She lost no more time in wondering what will happen to those idiots and hurriedly caught up to Snape and pulled at his sleeve till they reached the wall entrance she left no longer than fifteen minutes ago. She opened the passage and pushed Snape in, rushing after him and reapplying the wards again. She waved her hand and lit the candles. As she turned, she heard a surprised exclamation of 'It's YOU!' as she faced him.