Original subtitles

As long as we have gears and waterwheels,

the era of manual labor is over.

With an infinite contraption that requires no fuel,

we're finally harnessing the power of nature.

We're overcoming manpower

and entering the age of energy!

HYDROELECTRIC POWER PLANT OBTAINED!

What is this?

It's a hydroelectric generator.

Hydroelectric?

Generator?

This is really awesome, Senku.

The credit goes to Chrome and Mr. Kaseki

who made this huge waterwheel.

But it's not completed yet.

All our precious electricity is still leaking away.

So, what do we do then?

We need to create a box that can store electricity.

Can that spinning power be stored?

Yes, although it will be a bit of a pain to make.

This isn't the time to collapse.

We have a lot of high-difficulty crafting to do

before we get to our mobile phone.

This is bad.

The Spartan Crafts Club begins now.

This is so exciting.

To make a box for storing electricity,

in other words, the battery,

we need to dip these two lead plates

into our friend, the two-faced goddess, Sulfurina.

Sulfurina?

Do you mean sulfuric acid?

Send electricity into this and it will store power on its own.

It's simpler than you thought, right?

It's not simple at all. It's quite hard.

We'll need to make another five and connect them all.

Hasn't the Crafts Club been working too hard lately?

BATTERY OBTAINED!

Is it really being stored in these tiny containers?

All the spinning power from those disks--

It's really in there.

BATTERY

Does it mean that Kinro and I

don't have to spin that thing anymore?

Yes, never again.

Didn't I tell you?

This is the era of energy.

Long live energy!

I'm not surprised about the lazy Ginro,

but even the hardworking Kinro is happy about it.

Spinning that thing must be really exhausting.

It doesn't mean that you can take it easy.

I need both of you to work on other projects.

The fighters can focus on training now.

Show me what you've got!

The final battle is only a few months away.

We must step up our training to defeat Tsukasa and Hyoga!

Hey, there is no time to rest!

This is way too Spartan!

Mr. Kaseki is dying!

The waterwheel has another vital function.

Here comes the exciting gear-making session.

It will do wonders on the waterwheel's motion.

Damn, it broke again.

I need to copy the designs again.

The teeth on just half of the disk

catch the top and bottom in turn,

and that would turn rotational motion into a back-and-forth motion.

These ideas humanity came up with are incredible.

It's unbelievable.

That's just so interesting

that it gets me burning with excitement.

Come on.

Leave the intricate work to the craftsman.

They were so worn out,

but when they see the design, they are being all tough.

This is…

It's the air-blowing machine for building fires!

Level one!

Level two!

It's now upgraded to level three!

LEVEL 3

This was the hardest work we had to do in exchange for ramen.

The hellish iron-making is finally mechanized!

-Long live energy! -Long live energy!

I told you. It doesn't mean you can take it easy.

The non-fighters can now focus on the winter preparations.

I've never seen all these before.

Is this called bottling?

It's the ancestor of canning.

I can have meat even in the winter.

It's heaven.

What's the Spartan Crafts Club up to now?

Light bulb.

Yes, he's a brilliant guy.

But I got so used to it now that I'm no longer surprised.

When the filament is lit, the temperature rises to 2,000 degrees.

That melted the metal connections.

We can only reinforce it with glass instead of super glue.

This job is so intricate.

It's tough even for me.

Damn it! It's just too hard!

What's the matter? Are you feeling discouraged already?

Not at all

although my body gave up a long time ago.

As expected of a craftsman.

I can always count on you.

My goodness.

I've been living an easy life in this village for 60 years.

Senku,

ever since you came,

it has been so much harder

and so much fun at the same time.

Aside from a few,

I bet everyone in the village feels the same way.

RAMEN

Didn't the filament burn out in an instant

the last time we lit the light bulb?

What do we do?

What do you do to keep something burning?

Use a blower to continuously give it air.

Like we did with the waterwheel, right?

What do you do to keep things from burning?

Get rid of the air?

We use the hefty weight of mercury

to catch the air as it falls

to create a vacuum.

That way, regardless of the temperature,

it will not burn as long as there is no air around it.

Then it won't burn out instantly and continues to light up.

Senku, I've brought everyone here!

All right.

A moment, please.

Any minute now.

Oh no. It's snowing.

Should we abort the test?

No, it's best to do it today.

It's ready.

All right.

Let's turn it on.

It's like the twinkling stars.

Illumination.

It feels like I'm back in the modern world.

It took us two months to get this far.

It took us so long.

No, it's as I planned.

Could it be that today

is Christmas?

I see. I think it is.

What a coincidence.

What a lie.

Awesome! I have an idea!

We can go deep into the caves farther than we could with torches!

-Isn't that right? -Yes.

With batteries and light bulbs, we could go ten billion times deeper.

There must be a lot of magical stones deep in the cave.

Let's have a science expedition.

We'll find some great resources!

Senku, I can't beat you in science.

But I'm more experienced than you when it comes to expeditions.

I'm sure. You've had years at it.

What do you need?

I, the expedition leader, will bring them to you.

There must be a lot of materials

in the roadmap for the mobile phone that we don't have, right?

Right, the missing materials…

-There isn't any. -There isn't any?

We have everything.

I've got everything in the missions we worked hard to accomplish.

Is an expedition even necessary?

We're short of manpower right now.

I bet he just wants to go exploring,

now that he has some new gear.

I still need a lot of copper though.

There is no telling how much we're going to use during our next crafting session.

All right. That's it!

Leave it to me!

Come back soon.

Return by next week, before the new year.

So what will this crafting session be?

I want to finish it before Chrome returns

to give him a surprise.

An upgraded version of the light bulb.

Making light bulbs is hard enough. This is so exciting.

We're making computer eggs.

The gears of electrons.

The vacuum tubes.

Vacuum tubes?

Finally, here comes something that I know nothing of.

Well, I do know what it is.

I've heard of it before.

But I don't know what exactly it does.

They emit electrons at high temperatures,

letting us control the direction of the current and making it stronger.

Just think of it as the gears of the electricity world.

It's the core of a mobile phone.

It requires a lot of work.

But isn't it almost the same as making the light bulb?

Yes,

but since it is called a vacuum tube, we really need to remove the air.

In other words, we have to get rid of the air completely.

So, I added phosphorus to the filament, where it will heat up.

When it burns up,

it can absorb the air around it.

I didn't do anything.

It cracked at the base.

The wire expanded?

The metal line going through the glass

expands just a little from the heat of burning phosphorus.

The glass broke because of these microscopic changes.

Is that the level of intricacy we're dealing with?

What do we do then?

Nothing ever works right

on the first try, does it?

It's nothing but trial and error.

Isn't that what we usually do?

Hey, I'm back!

What do you think?

Wait. No pun intended.

The copper came just in time.

A tube made of copper?

A copper tube

will just expand inward

without cracking the glass around it.

Finally!

My goodness. It's so tedious to make a vacuum tube.

Oh no.

The bamboo filament burned out instantly.

Damn.

The bamboo filament fundamentally couldn't last in the vacuum tube.

I don't understand science.

But in short, bamboo is too weak, right?

What do you need?

If you need something stronger, I'll find it for you.

No.

It just doesn't exist in this era.

How about this?

I brought as much material as I could from various caves.

I must find something stronger among these materials!

This looks like a gem.

That's a jewel bug corpse.

No!

How about this?

The color is really dark but it's light.

-It's a raccoon's poop. -Shit!

I've come to the stage

where I'm finally stuck.

I'm not a rock expert like Senku.

But I often play in the forest and mountains.

So I've seen a lot of rocks.

I'll find some rare rocks that might be useful to him.

I want to help him out.

If that's it for mobile phones, then that's it.

There is no time to be in despair.

I have to think of some other ways.

Senku, time to wake up.

It's the new year.

We should all watch the sunrise together.

It's important to have a change of pace and a fresh mindset.

That's my job, right?

Mentalists are so annoying.

I'm coming with you!

Wait, Suika. Were you going through rocks all night?

Suika wants to help out too, right?

That's right.

It's the new year, right?

Our body's internal clock is a mess because of the petrification.

I don't even know my age now.

Just count the days you have been alive.

How can we possibly remember that?

Senku, you…

It's 6,268 days.

We're almost there.

The sun's rising.

It's blue.

Is it a gemstone?

It's beautiful.

This is…

Why is it glowing?

It's called scheelite.

It emits blue light under ultraviolet light.

Reactions to ultraviolet light are especially visible

before the sun rises,

which is only right now.

It's a magic stone that only shines for a moment.

I've never seen anything like it.

Yes, me too.

This is an extremely rare ore.

Thanks to Chrome and Suika's great contribution!

This is used in filament in the modern world.

Atomic number 74, tungsten!

It can withstand high temperatures.

The strongest metal in the universe!

This small chunk won't be enough.

But it came down the stream in the cave.

There must be a lot further inside.

Tons of this heat-resistant treasure called tungsten!

There is only one set of lights left.

The last member of the expedition will be…

You can't pick me.

I need to train the fighters.

Who should you pick then?

If you pick me, I'll gladly oblige.

No, it's too scary.

Find someone else.

If you pick me,

I'll do my best to help.

I can go if you want me to.

But an expedition into the cave?

My back may give out.

You don't need a mentalist in the caves.

Magma!

Collecting heavy scheelite requires a lot of strength.

The friendly expedition trio

will go on a mining expedition together.

To the fun treasure dungeon!

Friendly?

NEXT EPISODE

THIS IS A WORK OF FICTION.

MATERIALS AND METHODS ARE BASED ON REALITY.

DO NOT ATTEMPT FOR YOUR SAFETY.

Subtitle translation by: Angel Choo