Based on the events in chapter 674.
Your name is Usopp, you are a Straw Hat pirate, and at the moment, you are freaking out.
"Master," squeaks Sanji - no, not Sanji, Nami, even if he (she, it) has Sanji's voice.
Master… who is this guy, what is this guy, his body twisting and curling like smoke, like gas - which you guess can be explained by a devil fruit (what can't be? you sometimes wonder), but what about those horns? For a second you think of Merry (the person, not the ship, but is there really ever a time when the Merry Go isn't at the back of your mind?), and then you're brought back to reality - horrible, terrifying reality - because Sanji (Nami) is shouting at Master, fury in her (his) eye. Master's holding up a bag of candy and grinning widely.
"Come, children, we must get you away from these horrible people," he says, voice all calm, too calm. When you realize he's calling you and Nami (Nami, not Sanji) horrible people, anger flares in your stomach. Sure, you're pirates, you're criminals, but you're nowhere near as horrible as him.
The kids are staggering forwards, eyes rolling, frothing at the mouth, even worse than the zombies back on Thriller Bark because these are children.
"Wait! Don't go! Do you wanna go back to the lab?" you shout. You can hear Nami trying to coax the kids, too. (Nami's words, Sanji's voice, and every time you hear it there's a weird feeling in your stomach.)
You're distracted long enough for the kid's fist to connect with your face and you go down hard. Kids shouldn't be - can't be - this strong.
"Usopp!" Sanji's voice, Nami's words. And then Sanji's hands helping you up with Nami's gentle touch and you shudder.
And then she's (she she she, not he) throwing herself at the kids again.
"Don't touch me, cockroach!" one of the kids yells, shaking Nami off easily. You see red. Nami's not a cockroach! (Sanji doesn't look like a cockroach!)
You ready your Black Kabuto, but Nami's grabbing at you, pleading, "No, no, don't hurt them!" while Sanji's strong hands (were they always so feminine?) hold your wrists tight.
You try to protest - these kids are going to kill you both (trap Sanji in a body that isn't his) - and then one of the kids' too-big fists connects with the side of Nami's (Sanji's) face.
She goes down easily (it's like a shock to your system, seeing Sanji so weak).
"Bastard!" The time you're going to kill that kid, protect Nami (and Sanji's body).
"These kids are victims! It's not their fault!" (Sanji's body is still tough, she looks mostly unhurt, good.)
"They're hallucinating! They called you," (called Sanji) "a cockroach!"
"If you're going to be angry at someone, be angry at him!"
You look over at Master - so calm, so sinister, the calm ones are always the deadliest.
"He's the one drugging the children!" It might be Sanji's voice, but these are Nami's words and Nami always knows what to say - to get what she wants, to say what needs to be said, to get you right in the heart.
"Take this, gas bastard! I have a special move that works against gas!" It's an old attack, not from Bowin Island but from before, and it's familiar and easy and it works-
It doesn't work.
Your firebird star fizzles out and how-
"Fire can't burn if you remove you remove the oxygen!"
And then you can't breathe. (And this is nothing like a panic attack, it's a thousand times worse, you try to breathe in but there's nothing to breathe.) Your fingers clutch at your throat and you crumple to your knees and you hear Sanji scream (not Sanji, Nami, except that doesn't make sense and why is your brain so fuzzy?).
When the giant pipe is about to crush you both (all three of you) and your world is going black around the edges, you realize with dark certainty that you've failed the two people who mean the world to you. (And everyone else that matters to you, because without Sanji and Nami, the crew isn't the crew - sorry, Luffy.)
...
Nami comes over to you, swinging her hips (you think of Sanji in her body, of when those hips were - sort of - his). She is very much female again.
"Well, that was crazy," she says, throwing herself down next to you on the aquarium bench.
"Yeah," you say, because it was - Punk Hazard, Caesar Clown, Law… You've just finished your first adventure in the New World (except nothing is ever really finished, not when you're a pirate, not when you're with Luffy) and you're on your way to another island with another adventure and you wonder how many more adventures you can take before you die.
"You have no idea how good it feels to be back in my own body," Nami informs you, hugging her own shoulders like she's afraid she just might slip out again.
"I'm glad," you say, leaning towards her. You give her a quick peck on the lips. "It was confusing when you were Sanji."
She grabs you by the shoulders and kisses you deeply - she tastes perfect, oh God you missed this when you were apart for two years.
You kind of lied, though (because that's still a thing you can do, even if you're trying to stop, sorta). You're not glad she's back to normal - not completely glad - because you never got a chance to kiss her when she was in his body. To feel Nami and taste Sanji and to have them both in your arms at once.
It's a pretty brave (scary) thought, and you wonder if you'll ever get that chance.
