The group gathered in the workshop, the air thick with the scent of molten materials and anticipation. Senku stood at the center of the chaos, sketching designs for the gas masks they'd need to descend into the sulfuric acid cave. Around him, Chrome and Kaseki worked to shape the necessary components.

Kuri leaned against the wall, her arms crossed as she watched the flurry of activity. Her silver eyes followed Senku's precise movements, noting the subtle frustration on his face as he inspected a piece of glass.

"You know," she said, breaking the silence, "this would be a lot easier if you used alchemy."

Senku looked up, narrowing his eyes at her. "Alchemy, huh? You're always talking about that. What's your pitch this time?"

Kuri smirked and stepped closer. "You have the ingredients. You understand the structure. Alchemy would let you skip the hard labor and transmute the materials into exactly what you need."

Senku raised an eyebrow, intrigued but skeptical. "So, you're saying I could just… make these gas masks appear out of thin air?"

"Not quite," Kuri replied, her tone measured. "You can't conjure something from nothing. But if you have all the components, you can use alchemy to assemble them instantly. The trick is knowing your limits."

Senku mulled over her words for a moment before nodding. "Fine. Let's see if this so-called alchemy of yours can save us some time."

But Kuri's expression shifted, her silver eyes narrowing. "Not so fast. A gas mask isn't the kind of thing you should transmute."

"Why not?" Senku asked, his tone challenging. "If it's faster and just as effective, why wouldn't we?"

Kuri crossed her arms, stepping closer to the table. "Because alchemy isn't perfect. It assembles things, but it relies on your understanding of the object. If you don't fully grasp how something works—like the precise seals and filters of a gas mask—then the result might look fine but fail when you need it most. You could die wearing it."

Senku frowned, considering her words. "So you're saying alchemy is only as good as the person using it."

"Exactly," Kuri said. "You're a scientist, Senku. You know chemistry and formulas better than anyone. If you wanted to transmute something like a panacea from the right ingredients, you could probably do it. But a gas mask? That's craftsmanship. It's not your strength."

"We don't have time to debate," Senku said, waving her off. "We need these masks to survive the cave, and we're making them. End of story."

Kuri sighed but stayed silent as the group got to work. She watched as Senku and Chrome collected materials, laying them out on the table: glass, rubber, charcoal for filters, and metal for the framework.

After gathering the necessary materials Senku stood before the table, his hands hovering over the pile. Kuri stepped up beside him. Even though she thought it was a bad choice, her voice was calm and encouraging.

"Close your eyes," she said. "Focus on the structure. Imagine every part of the mask fitting together perfectly. You already know the science—now let the rest fall into place."

Senku hesitated but followed her instructions. He concentrated on the components, visualizing the gas mask's design down to the last detail. A faint, golden light surrounded his hands, and the materials began to shift and merge. When the light faded, a pristine gas mask sat on the table.

Chrome let out an impressed whistle. "Whoa! That looks amazing! If you can do that, we don't even need Kaseki anymore."

Kuri's expression darkened, and she turned to Chrome. "That's where you're wrong."

Senku picked up the mask, examining it closely. It was flawless in appearance, but something felt… off.

Kuri took the mask from Chrome and held it up to the light. "It's not thick enough," she said, pointing to the lenses. "The glass is too thin and uneven. It might hold up for a little while, but under pressure, it'll crack."

She turned the mask over, tracing the seams. "And the frame—alchemy didn't twist the metal evenly. It might look solid, but it'll break under stress."

"You can't just transmute something like a gas mask and expect it to work perfectly," Kuri explained, her voice firm. "Alchemy assembles materials, but it can't create functionality you don't fully understand. The seals might not hold. The filter could fail. And if it does, someone could die."

Senku's eyes flickered with understanding. "So, it's good for things I already know how to build, but not for something as intricate as this."

"Exactly," Kuri said. "You could transmute raw materials, like iron, and skip the forge. But a gas mask? You're not a craftsman, Senku. You're a scientist and a chemist. Don't risk your life—or anyone else's—on a shortcut."

She gestured to Kaseki, who had been quietly observing the exchange. "That's why we need him. He's a master craftsman. He can build these masks to work exactly as they're supposed to."

Kaseki blinked, his earlier uncertainty melting away into pride. "Well, if you're putting it that way… Guess I'd better make the best damn gas masks you've ever seen!"

As Kaseki returned to his work with renewed enthusiasm, Kuri turned back to Senku. "Alchemy isn't a replacement for skill or effort," she said gently. "It's a tool to complement what you already know. And you? You're good at chemistry. If you understand the chemical components and reactions, you could transmute the panacea, saving weeks of trial and error. But leave the craftsmanship to the experts."

Senku smirked, his earlier irritation replaced with respect. "Ten billion percent, you just gave me a crash course in alchemy. Not bad."

Kuri smiled back, her gaze softening. "And you're a quick study."

Chrome scratched his head, looking between them. "So… what you're saying is, we're still a team? Everyone has their role?"

"Exactly," Senku said, his voice steady. "And right now, our role is making sure those masks are perfect."

As the night stretched on, the group worked together, their collective efforts bringing the gas masks closer to completion. The blend of science, magic, and craftsmanship created a sense of unity that couldn't be shaken.

And for the first time, Senku felt the true potential of combining his world with Kuri's—a delicate balance of knowledge and trust that just might lead them to a brighter future.