Naruto is not really surprised. It makes perfect sense to take Nagato, Mei and Namiko prisoner, or at least, pretend to. Naruto is sure that is what Iruka really means to do.
"But if you're my Daddy, then why do you want to take us prisoner?" demands Namiko, trying to free herself from Naruto's Grandpa, with no success. "That makes no sense!"
"You are already our prisoner," says Iruka. "Remember?"
Naruto's Grandpa cuddles the struggling Namiko tighter.
Then Naruto's brain catches up to the other thing that is being said. "Wait!" says Naruto. "Iruka-nii, she's your kid, 'tebayo?"
"That is correct," says Iruka-nii.
"OH MY GOODNESS!" Naruto snatches Namiko off his Grandpa. THEIR Grandpa. "I HAVE A COUSIN! Or neice…" Naruto is suddenly very confused. "Iruka-nii, is she my cousin or my niece?"
"Your cousin," says Iruka-nii. "Now don't let her escape."
Namiko bites Naruto hard on the arm.
"Ow!" Naruto exclaims, but does not let Namiko go. "Stop struggling!" says Naruto as Namiko tries to punch Naruto in the jaw. "We're only pretending to take you prisoner! For show! It's not for real, it's just pretend so that you can all come to our village and talk to the Hokage!"
"Ah, I thought so," says the Mizukage, nodding. "And we will play along - NAGATO - so long as it is only pretend."
"Can I have her back?" asks Naruto's Grandpa, pointing to Namiko, who has momentarily stopped struggling.
"No!" Naruto says, pulling Namiko away from Arashi. "You already had a cuddle! It's my turn now, 'tebayo!"
"I AM NOT A BABY!" Namiko shouts, finally breaking free of Naruto and running over to her Mum.
"Yoink," says Iruka-nii as he grabs Namiko on her way past him. Namiko kicks at the air with her chubby little legs, but cannot stop herself from being tucked under Iruka's arm. "Come on, then." He turns and starts heading back towards Gravity Fails.
"Aw, but I want to see the temple!" whines Burifu.
"Come on then!" Naruto grabs Burifu's hand and drags her into the maze. "We'll meet you at the other end!" he calls over his shoulder.
Mei smiles at her daughter, who does not look happy about being passed around her Dad's family members. Namiko is sitting grumpily on her Dad's hip and scowling unhappily at him. Then she sees Mei smiling at her. "Mummy!" Namiko whines. "Make him put me down!" there are tears in Namiko's eyes.
Mei realizes that from Namiko's point of view, Iruka is her enemy. "It's alright," Mei says reassuringly. "He won't hurt you. You're his daughter."
"That's right," says Iruka, smiling at Namiko. "I wouldn't hurt you even if you weren't my kid."
Mei frowns at that. "What do you mean?" she asks.
"Iruka would never hurt a kid," says Arashi, grinning and walking up beside Mei. "It's very sweet, but it turned out to be a negative thing on some of his missions."
"I don't really go on actual missions any more," says Iruka, blushing. "Because if I have to fight a child, I just can't. It wasn't a problem when I was a kid, but now…"
Mei catches on to what they are really saying. "Are you saying that you were taken off active duty after a child beat your ass because you will not hurt children?"
"Yes," says Iruka, blushing. "It wasn't a problem when I was a kid myself…"
Mei is pretty sure there is a choir singing somewhere nearby. She NEEDS to marry this man. All her life, her dream was to get married, and now she knows who her husband needs to be: Iruka Umino. "The perfect man does exist…" Mei says, holding her hands to her cheeks and blushing.
"You can have him," Arashi whispers in Mei's ear. "It's about time he got married!"
"Oh…" Mei stops walking to blush some more. "I even have his father's approval!"
"Why is Mummy acting funny?" asks Namiko, curiously.
"Because she's in love," says Shisui. "People act funny when they are in love."
"Why do you have a blue mustache?" asks Namiko, as the group proceeds to the main entrance to the maze.
"Because my girlfriend's dad is mad at me," says Shisui, blushing. "She's having a baby."
Mei laughs. "So he gave you a blue mustache?"
"He also tried to kill and castrate me several times," admits Shisui, trying to look innocent.
Mei laughs. Then she sidles up to Iruka and walks beside him for the rest of the way to the main entrance to the maze.
They wait for a few minutes before the little red haired girl in tie-dyed clothes and Naruto emerge from the maze. "It was windy in there!" Naruto says, grinning, holds out a camera to Arashi. "I took the pictures for you, Grandpa."
"Hey, Bro?" says the little red head, running up to Iruka.
"Yes, Burifu?" says Iruka.
"Why is the sky blue?"
"Because of complicated sciency stuff."
Burifu pulls a face. "I don't like compikated skience." She crosses her arms and tosses her head. "Tell me a fun reason!"
Mei can almost see Iruka think fast. She is interested to see what he will come up with.
"Well," says Iruka, smoothly. "In the old days, the sky used to be boring grey. It had no colour at all. But the ocean had so much blue, that it thought it should share some with the sky. So one day, the ocean threw up some of its blue water to the sky in clouds. The clouds gave all the blue in them to the sky, making them turn all puffy and white. The sky turned blue, and it was so happy that it cried tears of joy, making the first rain. But the ocean was sad because it thought the sky was crying out of sadness at being blue. So the sun shone on the rain drops, making them turn into a rainbow so the ocean would know the sky was grateful for the gift of colour. And now, whenever the ocean can see that the sky's colour is beginning to fade, it throws up some clouds to turn the sky blue again."
Burifu nods thoughtfully, chewing over that explanation. Finally, she says, "I like that reason. I shall tell it to my children, and grandchildren, and great grandchildren, and great great grandchildren."
"I like it too," says Naruto, nodding. "I shall tell it to my children, 'tebayo!"
"Thanks, Iruka, dude," says the really old man dressed in tie dyed clothes. "Now Burifu will tell everyone that reason and it will become the Order of Steve's official explanation for why the sky is blue."
Mei eyes up Iruka, trying to figure out where he hid the sacred scroll. If she can get the scroll and Namiko back, then she will be able to escape. Nagato can take care of himself. Despite the assurances that the Leaf shinobi are only pretending to take Mei, Nagato and Namiko prisoner, Mei has studied enough history to be cautious of those promises.
Iruka sees her looking at him and says, "You can't have the scroll. We have permission to take it back to our village, so if you want it, you need to make an alliance with the Leaf and study it in the Leaf."
"Gurunku will not let the scroll past the barrier if someone has it without his permission," adds the old hippie. "The old dude knows everything that goes on in this place, eh."
"That I do," says Gurunku himself, appearing seemingly out of nowhere. "I invented a seal that will tell me if an ant so much as breathes within a certain area. Nothing happens in Gravity Fails that I do not know about."
"Oh, that's the seal Iruka sensei uses to monitor his house!" says the Hyuuga boy. Mei really needs to learn their names.
"Oh, do you use my seal?" says Gurunku, smiling at Iruka.
"Yes I do," says Iruka. "I have to keep Naruto safe."
"WOW!" Naruto stares up at Gurunku with big, sparkly eyes. "You're an awesome seal master!"
"Yes, yes I am," says Gurunku, nodding. "And if you study hard, I am sure you will be a master too."
"Oh, I'm already a Master," says Naruto. "I became a master, like, a few weeks back when we were at the Temple of Jashin. I just have to get the awesome part down."
"Well done, boy!" says Gurunku, slapping Naruto on the back. "Your handler must be something else!"
"Iruka-nii is the s***," says Naruto.
"Naruto, language!" Iruka and Arashi say in unison.
"Sorry, but Iruka-nii IS totally awesome, dattebayo!"