Goku and his friends -- Zenitsu and Inosuke -- just landed inside the Mugen Train. On Goku's back, there was Tanjiro's box, where Nezuko was lurking. Unfortunately, due to his broken arm, Tanjiro didn't join the mission, but Nezuko did, to help the others.
"What are we gonna do now, boss?" asked Inosuke.
"First of all, we have to find Rengoku, the Flame Hashira. They told me he's around," explained Goku, "then, we'll see what to do alongside him."
"Fine, you're the boss here," said Inosuke, "let's go, Monitsu."
Thus, Inosuke and Zenitsu followed Goku, like two young brothers who followed their elder brother. While walking, Goku looked around the train to see if there was any possible threat.
"Always stay vigilant, Zenitsu-kun and Inosuke-kun," he said.
"Understood, boss!" exclaimed Inosuke. Suddenly, when Goku jumped from a wagon to another, Inosuke noticed a window of the train. To a normal person, it would seem normal. But to Inosuke, who grew up in the mountains, a window in a train was something utopic.
"Whoa!" he shouted, getting close to the window.
"Do not procrastinate, Inosuke!" said Zenitsu, grabbing him from behind, trying to pull him away. Instead, Goku kept moving straight. All the passengers were watching him.
(Why are they staring at me like that? Is it because of those two?) He wondered. Suddenly, Goku heard a voice.
"UMAI!"
"Who's this guy..." wondered Goku. Zenitsu, who managed to pull Inosuke away, followed Goku. As they entered the other half of the wagon, Goku noticed a guy.
"UMAI!"
This guy had yellow hair. Goku immediately recognized him.
"Kyojuro!" he exclaimed. Rengoku turned to face him.
"UMAI! You should try this ramen, Goku-kun! It's very umai!" said Rengoku, who was sitting on one of the chairs of the train.
"Really? Guess I'll give it a try," said Goku. The boy turned and saw that, once again, Inosuke was trying to jump outside the window, with Zenitsu trying to drag him away.
"I wanna go outside and see who's faster between me and this thing!" yelled Inosuke.
"Are you insane, Inosuke?" asked Zenitsu.
"Those two... are truly incorregible..." sighed Goku, despairing.
"Why don't you sit here, Goku-kun?" asked Rengoku, patting the spot next to him.
"Uh, yeah," replied Goku. After placing Nezuko's box safely at the edge of the seat, Goku sat down.
"So, why are you here?" asked Rengoku.
"Demon, as always," said Goku. "What about you?"
"I had to investigate the disappearance of forty people inside this train."
"That's why you've been away for all this time... Honestly, I thought you were dead..."
"Ah! I'm a Hashira, I'm hard to kill, you know!"
"I hope so..."
Suddenly, the door of the wagon opened, and the train conductor arrived.
"He's here to check our tickets," explained Rengoku.
"Oh, I see..." said Goku, (I don't know why, but these tickets smell like danger...)
"Listen, Goku-kun..." said Rengoku, "once this mission is over, will we keep training?"
"Of course we will, Kyojuro!" exclaimed Goku, smiling. Then, the train conductor checked both tickets and obliterated them.
"Mmmhhh..." muttered Goku.
"What's going on, Goku-kun?" asked Rengoku.
"I don't know. I just know these tickets are tricky. But maybe, I'm just imagining things."
Suddenly, the lights went out. Then, a second later, they came back on.
"What... What's happening...?" muttered Goku, standing up.
"Nothing... Nothing at all..." muttered the train conductor, whose eyes weren't visible due to his visor hat. Then, the train conductor left.
"What a strange guy..." muttered Goku.
Suddenly, Rengoku stood up.
"Mr. Conductor," he said, "as this is an emergency, please act like you didn't see my sword."
"Kyojuro, what are you..." tried to ask Goku. But at that point, the lights began to go off and on rhythmically. Until, suddenly, a demon appeared.
"Shit! A demon!" yelled Goku, already drawing his sword. But Rengoku was faster than him. In the blink of an eye, the Flame Hashira rushed forward, towards the demon, who had multiple, distorted faces and a sumo fighter-like physique.
"Flame Breathing: First Form..." said Kyojuro, rushing behind the demon's back, "Unknowing Fire!"
In a fraction of a second, the demon's head got severed, and the threat was seemingly over.
"Okay, maybe a little showoff, Kyojuro..." commented Goku.
"There's still one more," said Rengoku, "Come with me."
Goku didn't have to be told twice, and immediately followed Rengoku.
"Don't leave me behind!" yelled Zenitsu. Then, the four of them found themselves in the other wagon, with a spider-like demon terrorizing it.
"This one's mine!" exclaimed Inosuke, rushing forward.
"Don't be stupid, Inosuke-kun!" said Goku, but Inosuke didn't seem to listen. The demon took Inosuke and almost hit him. But fortunately, Rengoku arrived at godly speed and put Inosuke in the seat.
Then, Goku took another passenger in his arms and brought him away. Then, in unison, both Goku and Rengoku rushed forward.
Flame Breathing: Second Form -- Scorching Rising Sun!" they both exclaimed, and the demon's head got severed.
(Those two... really are incredible...) thought Zenitsu, admired.
"You know what you're doing, from what I see!" exclaimed Rengoku.
"Yes, I do!" replied Goku.
"It's clear I trained you well!" said Rengoku.
"I want to be trained too, Rengoku-san!" said Zenitsu.
"Yeah, me too!" said Inosuke.
"Fine! I'll train all of you once this mission is finished!" exclaimed Rengoku.
"Yes! Big Bro Rengoku!" exclaimed the trio in unison.
Times later, the four of them -- Goku, Rengoku, Inosuke, and Zenitsu -- fell asleep. Goku and the Flame Hashira were sitting together, with the first resting his head on the second's shoulder. On the other hand, Zenitsu was deeply sleeping, and Inosuke was lying on his legs, loudly snoring.
However, this wasn't a coincidence: Everyone on the train was sleeping. But why? However, the train conductor was rushing forward until he arrived at a wagon and bowed down.
"I did everything you asked me to!" he said, "just make me fall asleep and see my daughter and wife again!"
Suddenly, from the ceiling, a strange hand with a single eye on the palm appeared and spoke up.
"Fine. You've done a beautiful job," it said, "as promised, now, go to sleep..."
And suddenly, as if by magic, the train conductor fell asleep. Then, the hand turned back to see four kids, still awake.
"What should we do now?" said a little girl.
"Not that much," said the hand, "their slumber will grow deeper with time. Just wait until then, and then make your move. When you tie the ropes, be careful not to touch their bodies."
The four kids nodded.
Meanwhile, in the other wagon, Goku -- just like everyone else -- was unaware of what was about to happen.
Chapter 14 - End.