One Piece is the creation and property of Eiichiro Oda. I have no ownership.

Sitting on the remains of a stone wall in the ruins of Kurau City on Zou, Usopp continued to make last minute adjustments to the new sorcery clima-tact for Nami. From the moment she announced that she would be going with Luffy to rescue Sanji, the sniper worked non-stop to assure that his female crewmate would be prepared. They may be two-thirds of the "weak trio" in the Straw-hats, but Usopp could tell how important this was to the navigator if she was willing to risk going on such a dangerous mission. What exactly happened between her and Sanji to make Nami so serious about rescuing him?

Examining the mechanisms and polishing the surface, Usopp was proud of his improvements on Nami's weapon. Sure, Franky helped with the surface treatments, but the sniper was the one responsible for fitting all of the Weatherian devices into the staff along with the pop green growth capabilities. He was certain she would appreciate the stronger abilities and manageable size. Now he just had to show her how to use it.

As if on cue, Nami came into the clearing. She maneuvered through some of the Mink tribe and their affectionate greetings as she passed. Usopp hadn't even noticed the small group that formed to watch him work. "So," the navigator smiled at her crewmate as she folded her short skirt underneath her and sat down next to him on the remaining stones, "is it finished yet?"

…

Usopp completed his explanation of the new clima-tact to Nami… or, at least he attempted to. The navigator appeared to be too busy twirling her improved weapon around to actually pay attention to the instructions, which annoyed the sniper. He forgave her as soon as he saw her warm smile while she thanked him, though. It was such a welcome change to her mood since the remaining Straw-hats arrived on Zou the day before. He couldn't help feeling bashful.

Pulling out his small book of items, Usopp was still smiling as he thumbed through the pages. "Now then, the fee for the materials used…" The sniper's smile faded when he saw his crewmate disappearing in front of his eyes.

"Mirage Tempo!" Nami said sweetly as she turned invisible.

"Bailing on the check!" Usopp yelled at the woman. He couldn't hear her, but he somehow knew she was still there. After a minute or two, the sniper just closed his eyes and let out a sigh in defeat. He knew how stingy the navigator could be about money. Maybe if he tried a different strategy… "Well, at least your Mirage Tempo works well." He put his book back in his pocket and began to put away his tools. "Something tells me that you're going to need it."

There was another pause. "Hey, Usopp," Nami said softly, finally breaking the silence. The Mirage Tempo faded to reveal that she was sitting on the stone wall again. Most of the Minks had long retreated and those that remained were talking amongst themselves at a distance from the two pirates. The sniper was about to harass his crewmate about the cost of materials again, until he saw her face. The navigator appeared to be lost in thought. The anxiety in her voice was palpable. "What if…" She closed her eyes and took a breath. "What if he doesn't come back?"

"Oi, oi, Nami." Usopp's voice trembled as he tried to assure his crewmate. He never could hide his nervousness. "Sanji will come back. He's bound to come back, especially if you're with the retrieval team."

"I'm not so sure about that," Nami responded. The last somewhat intimate moment she and the cook had was her knocking him through a thatch roof after he saw her in the Mink dress. It was his fault for making that stupid perverted face, though! If she had known that it was the last time they would be able to speak privately to each other, then she would have been nicer.

Usopp could no longer refrain from asking. "Did something happen between the two of you while we were in Dressrosa?" Nami blushed a bright pink. The sniper continued, "I mean, ever since we got here, you've been pushing to go after him. You just seem really weird about him now."

The navigator unconsciously brought her free hand to her now flushed cheeks, unaware of how guilty she appeared. She couldn't tell her crewmate about the evening she spent with Sanji in the library prior to landing on Zou. In fact, she didn't really feel comfortable sharing that with anybody. She had only just realized her feelings for him. How could anyone else understand?

Looking down, Nami thought of an alternate reason. "You didn't see his face when he left," she told her crewmate. It wasn't a complete lie, but more of a half-truth without revealing her feelings. She turned to Usopp. "The smile he gave us…" The navigator deeply exhaled. Tears stung the corner of her eyes as the stress began to tighten in her chest. Knowing Sanji wasn't there to help relieve her anxiety this time, she tried to breathe through the fear. "He told us that he would return, but… he smiled like he knew he would never see us again."

Judging from her reaction, Usopp could tell that something formed between the cook and the navigator. He didn't know the extent to which their relationship had developed, but it was enough to make Nami care about Sanji… at least in a way that was different from how she cared about him before. The sniper felt embarrassed. He couldn't think of anything to say to comfort his female crewmate.

Thankfully, Zoro came into the clearing, sparing Usopp from having to try to find the words. "Hey, Nami," the swordsman's voice was as gruff as ever. "If you're going to help Luffy recover that curly idiot, you better hurry. The captain is ready to leave." The navigator let out a groan as she ran off to collect her things.

Once Nami was out of sight, the sniper turned to his green-haired crewmate. "Um… Zoro," he said in a shaky voice. "Do you think something happened between Nami and Sanji?"

"If it did," the swordsman glanced at Usopp, "then all I can say is it's about damn time." With that, he turned and left.

The sniper just smiled in response and picked up the last of his tools. He decided that he would charge Nami after she returned… and only if she didn't have Sanji safely with her. That was only fair.

Owari!

A/N: I wanted to show Usopp just beginning to use his Observation Haki. Since it was first awakened in Dressrosa, I don't think he would really have a grasp on it yet.

A/N-2: The "night in the library" that Nami is thinking about is a reference to another fic of mine, Disclosures in Tea. You can find it on AO3. ^^