The sunset became the backdrop of the five swimming boys who went to the hot springs.
"Why are we going to the hot springs?" asked Nagisa, excited.
"Well..." Makoto scratched his head. "Gou did say we need to relax a bit."
"It's also a good thing that we get to invite Rin to come along." said Rei.
"My pleasure...haven't relaxed in a while!" Rin put his arms on his back as they approached the hot springs.
Much later on, Nagisa was falling asleep while in one of the hot pools, but he wanted to stay awake for a while.
"W-where are you guys going?"
"Well, we're gonna check out if dinner's already ready." Makoto said.
"Stay right here." Haru added.
"Alrighty!" Nagisa smiled.
Hours passed and Nagisa was still alone. He felt sleepy again, but somehow managed to stay awake, despite closing his eyes for a bit.
"I better check out those guys."
Nagisa wrapped himself in a towel and headed for the corridors. He searched the room they were staying and there was no one there. Not even the other rooms nor the lobby contained a single person. Nagisa started worrying.
Grabbing a bunch of clothes, he goes outside of the place.
"Where could they be....?" Nagisa thought.
"Maybe...they're gonna pick up Coach Sasabe from the swimming club? I better go there and check it out..."
But as soon as he got there using the keys he found on their hot spring room, there was no one around. He checked the pool and his face become distorted.
"Haru-chan! Mako-chan! Rei-chan!"
He saw them almost lifeless and sinking to the bottom.
Nagisa then hurriedly took off his shirt and swam to save his friends. First, he carried Haru up to the surface.
"Stay there, Haru-chan...!"
When he swam for saving Makoto, Nagisa noticed his body was getting heavier, as if his shorts are choking him.
"What's going on...I feel...dizzy...."
"...but I have to save Mako-chan and Rei-chan!"
Gripping onto Makoto's arms, he rescues him, despite Makoto's largeness. Nagisa noticed something different.
"H-how was I able to carry Makoto that easy? I thought..."
And then, Nagisa felt that strange feeling again. This time, he was coughing and vocaled out.
"Ugh...what's going on with m--"
That's when Nagisa noticed it. He looked at his hands and they weren't the same. He was twice bigger than before.
"This pool...was like in that dream...when all of us got older...but...how..."
Nagisa shook his head, despite hearing a much-more matured voice come out of his mouth. "I have to save Rei-chan first!"
Coming for his friend, he also noticed that Rin was on the deeper side of the pool. Realizing his body has gotten bigger, he was able to swim faster and with a wider range. He quickly grabbed both Rin and Rei and took them to the surface.
All of the people he saved were still unconscious, and Nagisa was totally exhausted. Despite that, he tried to wake them all up.
"Hey....guys...wake up....it's me...Nagisa...I just got older for some weird reason when I jumped into the pool...."
But there was no response from any of them. He tried CPR on each of them but nothing.
"...wake...up....don't....die on me...."
Nagisa's consciousness started fading slowly, as he knelt to the rough pebbled surface and eventually, dropped to the floor.
"Even if....I had this body....to save you guys from drowning...what good is it for...if I can't wake up you up...."
Nagisa's tears reached to the edge of the pool, as his eyes closed.
"Shh--! Nagisa's waking up!"
"HAPPY BIRTHDAY NAGISA!!!"
Nagisa opened his eyes and rubbed them. He looked around, realizing he was surrounded by all of his friends - Haru, Makoto, Rei and Rin, as well as Gou, Ama-chan Sensei, Coach Sasabe, and even guys from the Samezuka Academy (invited by Rin) - Sosuke, Aiichirou and Momotarou.
"W-what!? B-but I thought I was...where am I...where's the hot spring...!?" Nagisa had a lot of question marks in his head.
"We wanted to surprise you while we made you fall asleep in the hot springs!" Makoto smiled.
"We had to carry you quietly all the way here to the fun park!" Rei adjusted his glasses.
"We hope you're happy, Nagisa." Haru handed over the cake.
"Yeah, after all, it took us a lot to get you here!" Rin added.
Nagisa's eyes shone like the sun and the sea.
"Whoa...!! Thank you, guys! I thought you've forgotten my birthday!" He was a bit teary, but happy.
"Say...uhm..." Nagisa was confused. "I thought I was....and you were...drowning....and I..."
And then Nagisa told them about his dream.
"Oh, I see. It was just like that dream that all four of us had..." Makoto smiled.
"Looks like you had more of it, huh?" Rin chuckled.
"Don't worry, Nagisa." Rei said, patting his head. "You'll definitely grow older, especially that today is your birthday!"
"Aww...! Thank you, Rei-chan!" Nagisa blushed.
"We put some aromatic spices on your side of the pool so you could have lucid dreaming. Looks like it worked." Haru said.
"R-really? Y-you gotta tell me what you put there, Haru-chan!" Nagisa was eager. "I gotta have more of that stuff!"
Everyone laughed, as they began the party for Nagisa's birthday at that theme park.
Meanwhile, Momotarou was asked by Aiichirou.
"Momo-kun...do you know that redhead guy we met earlier? He looked like he knew your brother very well."
"Mikorin?" Momotarou wondered. "Oh, he's a far relative. He just dropped by."