After capturing Lucas, Severus and the others immediately took the house-elf and Meilia back to the Prewett house.
When Muriel saw that Severus's group, having been gone less than five minutes, had actually returned with the Fawley's missing house-elf, she was utterly dumbfounded.
"My goodness! How did you find it?! It's been missing for so long! You..."
Lockhart silenced the clamoring middle-aged woman. He found some rope and securely bound Lucas, who was still Petrified.
Sirius, evidently possessing more experience with house-elves, instructed Lockhart to use a charm to firmly stick Lucas's hands behind its back, ensuring it couldn't move its fingers even if it regained mobility.
Once the two completed these preparations, Severus raised his wand and lifted the Petrification Charm from Lucas.
The moment it could move again, the house-elf let out a miserable wail!
It looked as aged as Kreacher, and its cries were just as unpleasant, like the croaking of a bullfrog.
"Lucas is guilty! Lucas has committed a great wrong... Sorry, Master... Sorry, Sir... Sorry..."
Sirius looked at the house-elf with contempt.
"There are still members of the Fawley Family alive, yet you left without a word. You abandoned the loyalty a house-elf ought to possess long ago."
Hearing this, Lucas stopped crying. It glared at Sirius with its large, bulging eyes, its gaze filled with anger.
"Lucas doesn't need to say anything to an ignorant, stupid dog who knows nothing! Even if it can speak human words, it's still a beast that can't enter through the proper door!"
Sirius was instantly enraged, but before he could bare his teeth and take action, Severus pressed a hand down on his dog head.
"Sirius isn't actually a dog. He's a wizard trapped in his current form," Severus first explained Sirius's situation, then fixed his gaze on Lucas's eyes.
"You mentioned 'Master' and 'Sir'. This proves you still have a master, correct? Or perhaps your master has never actually changed?"
Lucas didn't conceal the hatred in its eyes. It held its head high proudly.
"Lucas has never betrayed the Fawley Family! After Lucas dies, it will surely have its head severed and mounted by the fireplace as a mark of the family's honor for its loyalty!"
Sirius found this declaration so nauseating he couldn't bear to listen further. Dealing with Kreacher was irritating enough, and now, encountering another one, he simply turned and left the room.
Severus, however, had already keenly grasped the key point from Lucas's few statements.
"Your master hasn't changed, meaning you still serve the Fawley Family's young mistress, Meilia Fawley. House-elves never harm their own masters, correct?"
Lucas merely sneered, its head held high.
Severus paid no mind to its attitude and continued softly,
"Then, who is this 'Sir' you mentioned?"
The expression on Lucas's face stiffened slightly.
"You left the Fawley household after the Fawleys died to protect Meilia. But such planning and actions clearly couldn't have been devised by a house-elf alone. Someone else instructed you to do this."
Severus analyzed slowly and methodically, with an air of calm composure.
"This 'Sir' must not have been a stranger to the Fawley Family. The Fawleys were very familiar with him and trusted him deeply. It's highly likely that before they went to meet their deaths, they gave you orders to seek out this 'Sir' afterward and obey his instructions."
Lucas's body began to tremble uncontrollably. Its look towards Severus shifted from hatred to fear.
It had been tailing Severus's group and was well aware they had discovered something through their investigation. But what Severus had uncovered clearly exceeded its comprehension.
Its changing expressions, of course, did not escape Severus's notice, and this only further confirmed his suspicions were correct.
"You blew up that bathroom because you feared we would find clues there that could reveal this 'Sir's' identity, because you are terrified of your young mistress, Meilia Fawley, remembering what, or who, she has forgotten."
"That's why you panicked and attempted to snatch her away when you saw us rushing Meilia out of the house."
Severus paused here for a second, as if using that moment to synthesize all the clues he had uncovered.
"So, this 'Sir' is the person who cast the Memory Charm on Meilia. He told you that making your young mistress forget certain things was to protect her. The order he gave you was to ensure no one could break his charm, to absolutely prevent Meilia from ever recalling those past events!"
"No! No! It's not true!! You're speaking nonsense!!!" Lucas suddenly screamed.
However, everyone present could see this denial was insincere. Severus had already deduced everything, and he had spoken the absolute truth.
"Lucas was lying before! Lucas actually betrayed the Fawley Family long ago! The young mistress is not Lucas's young mistress! It's not what you said, it's absolutely not what you said!!"
As it uttered these words, it was clearly in immense agony, unable to control the urge to punish itself.
But at that moment, Severus pressed down on its thin, withered shoulders.
"No one wants to harm your young mistress."