Scene takes place during "Murder in the Dark" (S1E12) when Jack & Hugh are at Aunt Prudence's house to question the household after Marigold Brown's death.

Detective Inspector Jack Robinson knew that Mrs. Prudence Stanley was a force to be reckoned with, and on this particular day, he was granted a further glimpse into the steely resolve of her character.

Inspector Robinson, Constable Collins, Prudence Stanley, Dorothy Williams and Phryne Fisher were all gathered in Mrs. Stanley's piano room. The Detective was inquiring of Mrs. Stanley if anyone in the household had seen the victim that morning, as Hugh took notes. The victim being one Marigold Brown, the 16 year old daughter of Herbert Brown, the estate's stable hand.

"I'll have to ask my housekeeper, Mrs. Truebody," she replied. Turning towards her niece, she requested, "Phryne, would you ring the bell, please?"

A young man appeared at the side doorway as Phryne rang for the housekeeper. His stilted, uneven gait halting in a stance that was somewhat unbalanced. His shoulders pulled backwards, both arms rigidly bent at the elbows, hands hanging slack at the wrists. His mouth was twisted towards the right side of his face, as if the left had been partially paralyzed from a stroke.

Mrs. Stanley turned to address him. "I told you to stay in your room." She scolded.

"I w-want to play with Marigold," his voice was guileless and innocent. "Where… where is she?" He asked, his body wavering in a constant side to side motion as he spoke.

Prudence's lips pursed and a sadness filled her eyes, her gaze floated downward. Looking back up, her face and voice softened as she spoke to him. "She's sleeping, my darling boy."

Standing in his common interrogation pose, hands firmly buried in his trouser pockets, Jack Robinson observed the exchange with a furrowed brow, his eyes darted from the man in the doorway back to Mrs. Stanley unsure of the newest occupant of the room, and his connection to Mrs. Stanley.

Miss Fisher was returning to the room when her aunt's voice perked up, pointing out to the young man, "Ah… look who's just arrived."

"Cousin-cousin Phryne!" He happily hugged his cousin as she made a happy humming noise whilst wrapping her arms around him, a wide smile evident in her voice.

"And look what I have for you." The pitch of her voice ascended in excitement. "Gobstoppers! And they're ENORMOUS!" A loud rustling sound emanated from the small brown paper bag she held in her gloved hands as she pulled out the aforementioned sweet. The young man's eyes widened to saucers in disbelief and joy.

Mrs. Stanley's face returned to its stern demeanor. "You can't have them unless you go back to your room." She bargained with him. Granting him this boon in cooperation for following her demand. His eyebrows raised in anticipation.

Phryne shot a side glance of disapproval and disdain towards her aunt, as the excited young man happily took the bag. A look of conspiratorial glee erupted on his face as he made a beeline for his room, anxious to gobble up his treat.

Jack watched the exchange between the cousins. When Miss Fisher spoke to him, he heard neither a patronizing manner in her speech, nor a tone of pity. He only sensed an enthusiasm and an unadulterated protective love towards her cousin. The fierceness of her devotion to him and her joy of giving was evident in her every word and gesture. Some members of society, in dealing with someone of his particular circumstances, might condescend or talk down to him as if he were an uncomprehending child. Phryne did neither. She treated him as an equal.

The Detective's face settled into a placid, subtle smile and almost imperceptibly nodded towards the scene across the room. Hugh looked on, eyes wide, slightly uncomfortable.

Mrs. Stanley returned her attention to the Inspector. "As you'll see, Detective Inspector, my son is… well, his faculties are limited."

Jack's face relaxed and tempered his voice, keeping a soft edge to it as he replied. "We'll need to speak to every member of the household all the same. Including Arthur."

"Of course," responded Mrs. Stanley, her countenance once more draped in its matronly demeanor.

"The girl's father," the detective continued. "Where can we find him?"

"Herbert Brown?" Mrs. Stanley's eyes looked up then back towards the men as she appeared to be recalling buried information. "He lodges behind the stable house." Her mind suddenly seized on her missing housekeeper, and she asked herself in general, and no one in particular, "Where in Heaven's name is Mrs. Truebody?" She waddled determinedly out of the room, effectively putting an end to the interview.

It spoke volumes to Jack Robinson to discover that Prudence Stanley had bucked 'societal norms' and expectations in regards to her son Arthur's upbringing. Most 'high society' types would have shipped him off to an institution to care for him, effectively washing their hands of him in hopes of sweeping the whole perceived embarrassment of the situation under the rug. Mrs. Stanley was made of sterner stuff; an iron will that belied an underlying heart of gold. Traits, he expertly observed, that resided firmly in her niece. The Detective's estimation of the matron rose several notches.

Jack let his smile wash over his face as the gravity and depth of the scene between Miss Fisher and her cousin Arthur Stanley registered and settled into a corner of his heart.

'Champion of the underdog.' Yes… that was it. She collected and brought under her wing those who needed protection and care, when the world would seem to only want to do them harm. This was yet another aspect he loved about the inimitable Miss Fisher.

He filed this new discovery away for later perusal and investigation, smiling as he walked out of the room.

Notes:

It always bugged me that during this scene in the episode, when Arthur entered the room, Jack seemed to not know who he was (wasn't introduced to him), yet at the end of the scene he knows his name. I just rode with it.