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Language:
English
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Published:
2021-12-13
Completed:
2026-02-23
Words:
21,350
Chapters:
17/17
Comments:
5
Kudos:
29
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Dopamine, Serotonin, Oxytocin [DISCONTINUED]

Summary:

ドーパミン、セロトニン、オキシトシン

The world of mafia gangs is no stranger to Ishigami Senku besides the life of a high schooler in the metropolitan city of Tokyo, Japan.

They call him Mr Perfect, Sir Genius and other titles equivalent to it. He may seem charming and romantic to many, but deep down inside, he's just averse to such a thing called 'love'. His late father left hints of messages for him to read just to find out that he's part of an arranged marriage to a young woman who goes by Ruri.

But why was Ruri the ideal fiancée?

The priestess of the Karva Empire was already arranged to be married to whoever wins the Grand Bout but her sister, Kohaku, avoids anyone from winning despite having to meet a certain danger that leaves no trace behind. The King was furious and worried as Ruri caught a deadly disease while Kohaku was held hostage by Ibara.

However, after all the hardships aside on the day of Senku and Ruri's marriage, an incident happened that made Senku change his mind.

What happened during the wedding? Did Senku decide to pull a trick up his sleeve?

**All of the characters belong to Riichiro Inagaki and Boichi respectively

Notes:

Warning: Depictions of violence (war and murder with the use of weapons) may be seen. Other warnings include potential canon spoilers from the franchise itself. Readers are suggested to finish off with the manga with at least some progress with the American arc to better understand the characters and the story.

Edit: Season 4 is currently airing which is a great opportunity to learn more about the characters' dynamics

(See the end of the work for more notes.)

Chapter 1: Prologue

Notes:

Edited 1 Feb 2025: I'm back a few years later coming out fresher and better. So, I'll be rewriting the whole fic chapter after chapter before I continue the storyline until the end. Maybe I could get a physical copy of this?

Chapter Text

"Alright, next is Senku-Kun!"
The young boy stood up the second his teacher called out his name in class. It was an icebreaking session of some sort among the students talking about their ambitions.

"I'm going to space," Senku announced to his classmates.

They were all amazed to hear that, their eyes sparkling with joy.

"An astronaut! That's a great dream. Well, when you grow up..."
"No, I'm going immediately,"

The ambitious boy interrupted the teacher without hesitating. Everyone went speechless. After the class ended, Senku broke the silence with his little chuckle.

"Kukuku, then again, I'm just a kid who doesn't know the first thing about science,"

He decides to head to the library, his favourite place to study and search for tons of material. It's a sanctuary of knowledge. Every minute there feels like a fever dream to the young, curious soul. 

He muttered under his breath, "I'm going to study every last thing."
"I'm going to try everything."

On his way back from school, he talked to his father, Byakuya, all while reading a book related to astronomy with all the mind-boggling information and complex equations that your average kid won't be able to comprehend (except if they're a damn genius or just wants to challenge their mind). 

"I can't help you. But, Senku, if you're serious, you can accomplish anything through diligent application of science,"

When Christmas was around the corner, Byakuya wanted to surprise Senku with the best gift possible. Hours of thinking and racking his brain led him to rash decisions. He went as far as selling his car just to buy him something that his son could cherish for a long time. Is it all the worth? 

"I'm sure Santa Claus will give you the tools you need," Byakuya whispered to himself with a soft smile.

The anticipated day has arrived, Christmas Eve. Senku was astonished to see whatever was in his room - a whole set of equipment for scientific research. He couldn't believe his eyes at the sight. 

From that day onwards, he started to conduct various experiments and start up exciting projects just for the sake of it. Every of Senku's experiments left people speechless, especially his best friend, Taiju.

"You can burn things with the point of light from a magnifying glass," Senku started to monologue as usual.

An old man passing nearby made his comment, "What an adorable experiment!"

On another day, Senku conducted a thermochemistry experiment.
"Sand iron and aluminium foil are awesome!"
"The frying pan is melting from the thermite reaction,"

The same old man as before has been observing Senku's actions.
"How adorable...?"

Another day has passed, and Senku brought an odd-looking machine to the school field.

"The liquid oxygen for the injector boils off ten billion percent at a normal temperature, and it freezes when it's too cold."
"I'll have to keep trying with ethanol for a while until I switch it to kerosene."

Such words that Senku uttered kept the old man shell shocked.

Senku left the field for a while to get some resources just to find a group of seniors destroying his invention with their feet, leaving him devastated. Taiju rushed to the scene and defended Senku from those students, leaving the poor kid injured afterwards.

Senku went to the school's laboratory to quickly assemble a gun that shot out electrical waves and counterattacked the seniors.

Usually, Taiju will help Senku with his experiments by getting the bits and pieces from stores. Taiju walked into an electrical supply store and approached the cashier at the counter. 

"Sumimasen. I need a Raspberry Pi, a transmitter module, and this thing called a "gyro," He later arrived at Senku's house with the materials and observed Senku's progress with his invention.

"We'll use a good old Yagi antenna for the receiver. It's what they'd use for TVs," said Senku joyfully.

Whenever Taiju tags along with Senku during experiments, he can be reckless at times and make the simplest of mistakes, resulting in mini explosions in Senku's apartment block. Byakuya doesn't seem to mind, though.

When Senku was around 11 years old, he decided to make a mini rocket. Of course, Taiju and Yuzuriha wanted to tag along with the fun. Taiju walked into the school's laboratory with Yuzuriha and approached his friend.

"Senku, you said you'd try it with a light payload, right? I had Ogawa Yuzuriha-san of the crafts club make us three passengers,"

"It's seriously embarrassing, having a doll of myself. What are you even using these for?" asked Yuzuriha to Taiju.

Taiju didn't answer her question, absorbed with Senku's progress. Once it was all done, the trio left the laboratory to go to the field. Senku felt tired during the walk.

He put the three handcrafted dolls into the rocket. After a push of a button, the miniature rocket launched high up into the sky. It managed to fly up quite high until it was out of their line of sight. 

"It blew up at a high altitude," said Senku.
"Failed again?!" Taiju exclaimed, while scratching his head in confusion.
"Not entirely,"

Senku showed his monitor display to Taiju and Yuzuriha. Both of them got giddy with excitement the moment they witnessed the scene unfold.

The three dolls successfully ventured out to space, which made Senku recall a few phrases he said and heard before. 

"I'm going to space,"
"I'm going immediately,"

"You can accomplish anything through diligent application of science,"

Senku could hear the voice of his old man clearly in his thoughts, as if he's currently there with him.

But that's not the end of his glory days...

It's just the beginning. The beginning of a new start.