I watched the question marks in Ran and Sonoko's eyes.
Akihiko Tou offered a gentle smile. "It really was just a small assist."
The café owner, arms folded, beamed at him. "A minor tweak turned my shop profitable—I couldn't ask for more!"
Her praise glowed in Akihiko's calm gaze, making the girls lean in with renewed curiosity.
"Akihiko-san, what mathematical trick bolstered the café's management?" Sonoko asked, brow arched.
Raised amid the Suzuki Foundation's circles, she found business scenarios endlessly fascinating.
"Math and management?" Ran echoed. "They feel worlds apart."
"It's straightforward: a mathematical model," Akihiko replied.
He folded his hands. "Consider two products on your shelf: one moves fast, the other languishes."
"A savvy economist is first a mathematician—Wall Street hires Princeton grads for that reason."
"When you scale to macro levels, you need data-driven regulation. Math is the bedrock."
"There's a model called the Ritter equation—a marketing decision framework by an MIT professor."
"I simply gathered this café's inputs: stock, foot traffic, channel data, conversion rates, and fed them through that model."
"Everything else—menu, service, atmosphere—was the owner's domain. I just supplied the formula."
Sonoko's eyes sparkled. "Listening to you explain math—it's riveting."
Ran's smile widened. "I feel… a spark of interest in math for the first time."
Akihiko grinned. "When I discuss models, you two gaze at me so intently…"
Sonoko pouted playfully. "You notice?"
"Actually, Ran, you stare at him just as much," Sonoko teased, earning a blush from her friend.
Ran's cheeks flared crimson—pure, shy as a peach blossom.
A few maple leaves drifted past the window, stirring an intimate hush.
The trio sat in warm silence until Akihiko broke it. "Here—try the cold brew. It's excellent."
They sipped; the coffee slid smoothly, sweet without bitterness.
"I wonder," Akihiko mused, "when you saw me at Tower Bridge, did you ever suspect me?"
"Never," they chorused.
Akihiko cocked his head. "Not even a little?"
Ran shook her head firmly. "You could never be the killer."
Sonoko nodded in agreement. "You're kind and gentle. Besides, you turned down countless confessions—there were more attractive suitors than Mahime."
Her words warmed Akihiko's chest. In a world ready to distrust him, their blind faith felt like an oasis.
Ran added thoughtfully, "And as someone with a detective father, I know the heart of a forensic worker."
Akihiko studied her.
She continued, voice soft: "They face corpses daily, earn low pay, and endure misunderstanding. Yet they persist for truth. Never could they cross that line."
His lips curved in a slow smile. "Ran, you're truly angelic."
Her sincerity resonated deeply in his former pathologist's soul.
Ran took another careful sip, still rosy-cheeked. "I'm just… ordinary."
"You're anything but," Akihiko said, brushing a stray foam drop from her lip.
Their eyes met, the word "brother" lingering unspoken.
Ran's eyes brightened. "Please—call me Ran-chan, or Oni-chan."
Akihiko's smile deepened as the maple shadows danced around them.
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