Since Mona doesn't know a single thing about sailing yet—not even as much as Arion—she's nowhere near a qualified Navigator. So the system's "recruit a Navigator" quest doesn't really count as completed.
There's no time limit anyway, so it's fine to let Mona study first.
In a sea like East Blue, the sailing knowledge learned back in the fishing village is more than enough.
Empty‑handed from fishing, Arion puts his things away, gets ready to shower and call it a day.
He pushes open the door to the captain's cabin.
Inside, it's not just 2B. There's also Mona, with her skinny, delicate frame, lower ribs faintly visible, a waist you could circle with one hand, but a round, perky hip line and solid, full lower body.
Her skin is really pale—the kind of white with a hint of pink.
Mona turns at the sound too.
The two of them lock eyes for a few seconds.
Arion reacts faster and shuts the door before Mona can let out a witch‑like scream.
Girls are a hassle. It's been more than half an hour and she still hasn't picked a single outfit.
He leans on the rail, lets the wind blow over him for a bit, stares at the stars, listens to the waves.
Behind him, the cabin door opens and Mona finally comes out, having changed into something proper.
On top, she's still in Arion's oversized white dress shirt. On the bottom, she's in a high‑waisted, ankle‑length skirt, the shirt hem tucked inside to cinch her waist.
Mona marches over, fuming.
"Why didn't you knock! Don't you know someone was in there?"
"It's my room. Why would I knock?" Arion sounds perfectly justified. "You're the one who took forever just to pick some clothes. And you're blaming me?"
"Even if I'm picking clothes, I've gotta shower first, okay? How is that supposed to be fast?" Mona protests, then catches the implication. "Wait, you said it's your room? Then how come 2B…"
Arion doesn't bother to hide it.
"We share a room."
"Whaaaat?!"
Seeing Mona's shocked face, Arion asks, "You couldn't tell?"
"A bit. I mean, 2B looks so cold and distant, like some emotionless swordsman. She doesn't look like someone who cares about romance at all."
"Don't judge by appearances. 2B's actually pretty passionate."
Especially in bed—Arion can't even match her.
"Never would've guessed. Just… hmm… I'm staying aboard the ship, I won't be getting in your way, right?"
"What are you worried about? You're not the only crew I'm recruiting. More partners will join one after another, we'll form a whole team."
"That's good, then."
Mona's relieved.
If it were just the two of them as a couple and she's the only single one, how awkward would that be?
There's an old saying back home—if you interrupt someone's date, you'll get run over by a boar.
Mona definitely doesn't want to get run over by a boar.
"It's pretty late. If there's nothing else, go get some rest," Arion says, turning to lean back against the rail. "The world's a mess. Whether you've got something to do or not, don't leave the ship alone and wander around outside."
"Of course I know that. That's it then. Night."
Mona waves a goodnight and turns to head back to her room.
She walks a couple of steps, then suddenly remembers—he saw her while she was changing, and she never made him apologize. She's just gonna let that slide?
She stops short, pivots around.
And runs straight into a broad, warm chest.
"Why'd you stop so suddenly?" Arion wraps an arm around her waist to keep her from falling, and also takes the chance to feel how soft her body is.
Not soft.
Mona's too thin; he gets jabbed by her ribs.
Mona scrambles out of Arion's arms, flustered, face burning.
"Y‑you're just gonna pretend you didn't see me changing?"
"What do you want, then?" Arion looks at her oddly. "You planning to stare back at me or something?"
"Pervert!" Mona backs up a couple of steps, on high alert. "Apologize! At least apologize, okay? Or are you planning to throw your weight around as Captain and do whatever you want?"
"You really want an apology?" Arion looks surprised. "I barely saw anything. It was all ribs."
—What's worse than having your body seen is having it seen and then being insulted on top of it.
Mona admits she can't compare to 2B's lush curves, but it's not like she's literally all ribs and nothing else.
She may not have much, but there's at least a handful there.
And Mona's pretty confident about her waist‑hips‑legs combo—thin enough, perky enough, round enough, plenty of meat.
And all that, in his mouth, turns into "nothing but ribs"?
That sends her temper flaring. She clenches her fists and charges.
"Jerk! I'm gonna beat you up!"
Arion doesn't square up with her. He circles around the mast instead, playing at running laps around the pillar.
In this kind of game, Mona's actually pretty good. She lets out a cold little laugh, then melts into flowing water, surging ahead as a rushing stream.
This is a skill Mona learned under her teacher's "chase training"—turning herself into a torrent to move quickly.
It's called Flow of Illusion and Reality.
In just a moment she's on him. She bursts from the rushing water and tackles Arion by surprise, slamming him to the deck.
Pinning Arion to the deck, straddling his hips, Mona grins triumphantly.
"Run! Let's see who's faster, you or me."
"Okay, okay, you win," Arion surrenders. "It's my bad. I shouldn't have made fun of you for being all ribs. Your hips and legs are actually pretty nice—way softer than they look."
The words make Mona jump off him like she's been burned, putting meters between them.
"You bastard! Pervert!"
"What do you want then?" Arion sits up. "Can't tease you, can't compliment you. You're hard to please, you know that?"
"Anyway, you can't use my body as a joke!"
"Fine, my bad. I shouldn't've barged in without knocking, and I shouldn't've said anything about your figure."
Arion doesn't dare tease Mona too much. If he pushes her too far and she throws in the towel, he's in trouble.
Young girls are a pain.
"Hmph. No sincerity at all."
Mona shoots him a glare, flicks her twin tails, and heads back to her room.
Kind of tsundere, actually.
Arion doesn't linger on deck either and goes back to get his shower and sleep.
In the room, 2B is doing maintenance on Assistant.
Seeing Arion come in, she asks, "How did things go with Mona?"
Arion walks into the captain's bathroom without even closing the door.
"What could happen? She's just a kid. We were just messing around a bit."
"I thought you would engage in reproduce behavior with her."
"Huh?" Arion looks at Assistant in front of 2B. "The genes matched?"
"No."
"Oh."
Arion's not surprised. They're not from the same world—how could their genes match perfectly?
And people from Teyvat are all kinds of weird: some created by the Primordial One, some evolved from drakes, some formed from womb‑water.
A bit of reproductive isolation is perfectly normal.
"No one on this island matches either."
"No rush. I'm still young. We'll take our time."
"Mm."
Even so, 2B is a little disappointed.
She lifts Assistant from her lap and sets it on the table, instructing it to stay on watch for the night.
Then, as she unbuttons her nightgown, she walks toward Arion in the shower.
"I'll wash your back."
Arion understands what 2B's really after. She wants a lot more than just washing his back.