"But…" Russell continued, as if unwilling to let the details go, "how much noise would that make? And isn't there going to be a gap between the wall, ceiling, and floor?"
"The gap can be covered with decorative molding and baseboards. As for the noise—don't underestimate our engineers. With the right design, the finest craftsman can move a ton-sized stone door quieter than a woman's sigh."
The two exchanged glances, reading the same message in each other's eyes: They'd figured it out. The way the 'ghost' entered and exited the room.
"Riiing—"
Just then, the bell sounded, cutting off Professor Fields' eloquent lecture. The sleepy students, feeling as though they'd received amnesty, began packing up to leave.
"Alright, class, that's all for today," Fields announced, still dissatisfied as he set down the chalk and waved his hand. "Oh, right." He remembered something, turning towards Russell and Mary.
"Miss Morstan, Mr. Watson."
"Yes," they replied in unison.
"The topic you raised—dynamic connection using redundant space—is really quite fascinating. Yes, very fascinating. I want you two to make it the subject of your end-of-term report. I'm truly looking forward to your results."
"...?"
Russell stood there, dumbfounded. Why is my question now my homework? He glanced slowly at Mary, disbelief written across his face. Mary didn't look at him. The girl neatly packed her notebook away, her beautiful blue eyes curving, and a smile she could hardly contain appeared at her lips. Once finished, she looked back at Russell.
"Is there a problem, Russell?" she asked, raising her bright, sunlit eyes and smiling.
"No… nothing." Russell averted his gaze, resignation settling in. On the bright side, at least Mary Morstan was a top achiever—which was more than could be said for those who might not even know their next assignment, let alone struggle to find a teammate… Maybe he'd just managed to avoid months of wheel-spinning. At the very least, he now had a strong anchor to cling to if needed. And worst come to worst, he could always drag Charlotte along to help.
This is her fault anyway. If she dares say a word against this, I'll… I'll just take the civil service exams myself!
Having reached that conclusion, Russell could only comfort himself thusly.
Russell stood up with Mary, and together they exited the lecture hall for the cafeteria. They found a quiet corner; Russell took a double bacon and ham sandwich and took a big bite.
"So, my hypothesis was right, wasn't it?" Mary sipped her tea before speaking.
Russell said nothing, thinking as he chewed. Issues remained. There were still plenty of unanswered questions.
He swallowed and then looked at Mary. "There's still issues."
"Hmm?" Mary raised her brows. "What problems?"
"Two," Russell held up two fingers. "First, labor and material handling, building work or modifications—none of this can be concealed completely. Ms. Holly David said there's been no sign of recent renovations in the apartment, and elderly tenants, in particular, hate noise. Speaking of elderly tenants—that's the second, and more important issue."
He paused for emphasis. "The person next door is a woman in her seventies."
"A woman in her seventies?" Mary said, pausing with her tea, her expression puzzled.
"Met her yesterday," Russell nodded. "A very kind old lady. Do you think a seventy-year-old woman would have the energy or stamina to perform the magic tricks Professor Fields described? And besides, she doesn't seem the type to collect used coffee cups, spray herself with other people's perfume, or sleep in someone else's bed. That's the most fundamental and inescapable question: an elderly lady with slow movements, versus a major renovation project requiring precise calculation and heavy work. The two just don't add up."
Mary didn't answer right away. She gently set her teacup down with a soft clink, shifting her gaze from Russell to the window. Afternoon sun was just right, casting the distant clock tower's long shadow. The cafeteria buzzed with students in twos and threes, chatting about classes, plans for the weekend, and idle gossip—everyday youthfulness, in stark contrast to the heavy subject the two of them were discussing. Just like the old lady and that spatial magic.
No one knew how much time passed before Mary finally looked away, stirring her tea gently and watching the little scarlet eddy before speaking.
"Maybe we were heading in the wrong direction from the start?"
"What direction?" Russell asked, taking another bite of his sandwich.
"Time," Mary replied quietly.
Russell paused.
"Up to now, our guess has always been that the passageway is there now, built for Ms. Holly David. That's exactly why we worried so much about these issues." She looked up, locking her blue eyes with Russell's. "But what if—"
"What if that passageway has existed from the very beginning?" Russell finished her thought.
"As Professor Fields said, similar designs existed in some early Victorian buildings. Maybe, it was designed for a previous tenant, or even for the day the apartments were built—not for Ms. Holly David, but for some other purpose. The ghost just happened to discover it, and used it."
"Exactly," Mary said, dropping a sugar cube into her tea and stirring gently until it dissolved.
"That answers the first question." She sampled her tea, savoring the fragrance and sweetness. "Now, let's move to the second question: The ghost's identity."
"Doesn't that bring us back to our original hypothesis?" Russell asked. "We've already ruled out people hiding in Holly David's apartment."
"We've ruled out her unit," Mary said. "But what if someone's hiding in another apartment?"
…