It took her a few minutes to realise what it was and when she did, she couldn't react. She was frozen in fear and couldn't even lift her wand to perform a simple stunning spell.

All three heads of the three-headed dog were glaring at her and grinding their teeth as the door swung open from behind her.

'Stupid girl,' a familiar voice said angrily. She slowly turned to see Snape's cold eyes narrowing at her. 'What would you have done if Hagrid had forgotten to tie the beast up?'

Serria knitted her eyebrows with confusion. She had no idea what kind of beast it was or who the man Snape was referring to, Hagrid, was.

'Who is-' she began.

'Forget it, girl,' he said coldly and grabbed her by the wrist. 'Come.'

'No,' she said, trying hard to escape his grip. 'Where are you taking me?'

'We are going to Professor Dumbledore's office right now, understand?' he said. 'If you don't oblige, I'll have to report you to him.'

Serria immediately ended her struggle. Although she was angry at him, she trusted Professor Dumbledore and wanted to talk to him. She obediently followed Snape, who did not release his iron grip to the staircase leading to the headmaster's office.

'Sherbet Lemon,' he muttered, at once making the staircase spring into life, giving them access to the stairs. He dragged her up the stairs and shoved her into the office.

'Now, now, Severus,' a gentle voice said. A silhouette emerged from behind the bookcase and Serria immediately recognised him as Professor Dumbledore. 'You have no right to treat a student like that. Surely, she doesn't deserve to be humiliated.'

'She wandered into the third floor, professor,' Snape said, shooting Serria a look of disapproval.

'As the head of her house, it is Professor McGonagall's duty to decide her punishment. If she is unable it is my job, Severus. You cannot treat her in that way. Apologise to her at once,' he said.

'But, professor-' Snape began.

'I said to apologise to her, Severus,' Dumbledore ordered.

'Sorry,' he said grudgingly to Serria.

'Now, Evans,' Dumbledore looked at her. 'Do you have any justification for being on the third floor when I strictly said at the welcoming feast that it is out of bounds?'

'Yes, sir,' she said. 'Professor Snape held me in after class and was asking me personal questions. It intimidated me, so I ran away to hide from him. I'm sorry, Professor Dumbledore. I didn't realise that I was on the third floor.'

He shot Snape a warning glance not to speak and nodded at her.

'Thank you, Serria,' he said. 'You may leave.'

'So I'm not going to get punished, professor?' she asked. He shook his head.

'Not this time,' he said. 'I'll leave you with a warning this time. But be weary, if Professor Snape, Mr Filch, myself or anyone else finds you out of bounds again, you will be punished.'

'Thank you, professor!' she said and hastily left the office.

'That girl is a splitting image of that dead muggle-born: Lily Evans Potter,' one of the wizards from the paintings on the walls commented. Snape's eyes welled up at that and a cold tear fell down his cheek.

'That's enough, Phineas,' Dumbledore snapped at the portrait. The wizard in the portrait, Phineas Nigellus Black, fell silent. He looked at Snape. 'Stop it, Severus,' he commanded. At once, his tears vanished and he looked back at him. 'Why were you interrogating Evans, Severus?'

'Her last name,' Snape choked out. 'It's the same as her's.'

'Indeed,' Dumbledore said. 'But that doesn't answer my question, Severus.'

'I though the girl was related to her,' he said. 'So I wanted to know.'

'By her, you are referring to Lily, aren't you?'

Snape winced slightly at her name.

'Yes,' he said. 'She resembles her so closely, I had a suspicion that they are from the same family.'

'What you did, Severus, was wrong – regardless of the reason,' Dumbledore pointed out. 'As for your suspicions, they are correct. Serria is an unknown child. She is the secret twin daughter, born to James Potter and Lily Evans. She is the Potter Girl.'

Snape took a sharp intake of breath.

'They have a daughter?'

'Had, Severus. They are both gone. But otherwise, you are correct,' he said. 'She grew up in a muggle orphanage knowing of the fate of her family. She is now acting under my guidance. I told her to keep her identity a secret, which is most likely why she refused to tell you anything.'

'But she spoke of the traitor Black,' he said. Dumbledore sighed.

'Unfortunately, that is true,' he replied. 'Serria knows the traitor Sirius Black as her caring godfather; she is unaware of his betrayal and imprisonment in Azkaban. And sadly, I'm afraid we'll have to keep it that way until the time comes for her to realise the truth herself.'

Snape looked incredibly uncomfortable. He hastily changed the topic.

'Forget the girl, professor. But the boy is absolutely unbearable. His talent is mediocre, he is as arrogant as his father, a determined rule-breaker, delighted to find himself famous, attention-seeking and impertinent-'

'You see what you expect to see, Severus,' said Dumbledore, pulling out a copy of Transfiguration Today from his desk drawer. 'Other teachers report that the boy is modest, likable, and reasonably talented. Personally, I find him an engaging child.' Snape huffed with annoyance.

'I'm leaving, professor,' he said and quickly turned to leave.

Dumbledore turned a page, and said, without looking up, 'Keep an eye on Quirrell, won't you? He seemed rather strange at the welcoming feast.'

Snape nodded curtly and left the room.

'Dumbledore,' Phineas Nigellus Black said indignantly from his portrait. 'Must you always insult the honorable Black family. Sirius did not do anything wrong. He, in fact, helped the Dark Lord in his noble quest.'

'Be quiet, Phineas,' Dumbledore said sharply, silencing the portrait. 'And do not let anyone else hear you say that, as they will most likely smash all of your portraits with rage.'