Train (Teurein / 트레인)

That night 12 years ago.

That's when we went into two different worlds.

I met Seo Kyung. But you didn't.

That's why... - This world is...

very different from your world.

It's time you go back to where you belong.

I'm going to catch him. The real killer is someone else.

He kills people the same way he killed your father...

and leaves a piece of jewelry there that he took from your house.

That is his signature.

There he comes. The victim's son.

I saw him. - He has a spot...

on the back of his left hand.

Lee Sung Wook isn't the killer. There's an accomplice.

He's the real killer. - But I found out...

that you were also a victim.

I'm sorry. - You were right.

Eventually, I have ruined your life.

Then, let's go back to that day.

April 8, 2008.

The culprit was in the house. When I went inside.

What about his face? Did you not see his face?

I guess you really can't avoid fate.

This is an antipsychotic drug.

It's normally prescribed to patients with Huntington's disease.

I checked the list of evidence and photos of the crime scene,

but I also didn't see a prescription bottle anywhere.

That means the culprit came back.

It was probably a kind of drug that could easily reveal his identity.

Mr. Seo? I thought you were at the nursing home.

It's you. The reason that jerk won't leave this world.

That jerk changed a lot of things.

Father.

Father.

Father!

I'll look inside.

Father. Father!

Father!

Get up.

Do Won.

It's you.

The owner of this necklace.

It wouldn't be bad...

for father and son to die at the same time.

It may seem like the end, but it's not over.

In the end, I didn't get to catch you myself,

it's not over.

I will eventually catch you.

Father!

Father.

Father.

Mr. Seo.

Mr. Seo.

Do Won.

What happened?

Ms. Oh.

Father!

Father.

Hang in there.

Do Won.

What happened?

Mr. Seo...

How did this happen?

Please run his fingerprints.

And find out who this guy is.

What happened?

What on earth happened to him?

Who on earth are you?

The real Seo Do Won is dead.

Who are you?

I am the dead Seo Do Won.

And the dead Seo Do Won...

is me.

From another world?

Mukyeong Station is the connection between these two worlds.

On rainy nights,

at 9:35pm,

Train 8210 arrives at Mukyeong Station.

Do you expect me to believe that?

Then, how else can I explain myself being in this world?

When I was in the 10th grade, I hurt my arm in gym class.

I'm sure you remember that too.

You were the one who went to the hospital with me.

It was 12 years ago when the world split into 2.

Since then, everything has changed.

The real culprit used the boundary to cover up his murders.

I don't understand this at all.

I neither follow what you're saying nor know who you are.

We just have a different memory of 12 years ago.

In the world I was in, and even in this world, you are...

my only friend.

I don't care who you are...

or where you came from.

To me, you're not the Do Won I know.

The Do Won I know...

died today.

Because of you, he had to die as a John Doe.

No one will know that he died here tonight!

I need some time...

to understand the person I have been working with...

and to figure out what to do now.

I need time to think.

The surest way to confirm that would be checking my body.

I will consent to any tests you ask for.

I have...

never done drugs.

I know I was the suspect of Lee Jin Sung's death...

and put Kim Jin Woo in jail even though he was innocent.

But I don't care who I was or how I lived in the past.

The only thing I can do right now is to do what I can in this world.

And right now, all I know is that Kim Jin Woo isn't the culprit.

Lee Jin Sung was killed because he saw the real killer.

He's the one who took and killed Jung Kyung Hee.

Other than them,

there are more missing people that he killed.

I myself saw their bodies.

We checked the surveillance cameras at the nursing home,

but we didn't see anyone else other than your father.

So you're telling me that he went outside...

because of delirium?

That's what the doctors claim.

That's how it looked in the footage, and his room was a mess.

End-stage liver cirrhosis patients often show delirious symptoms.

The hospital will be held responsible...

for not taking care of him properly.

And the Traffic Unit is investigating the accident.

Thank you.

Why isn't Inspector Han coming to the funeral?

Do you think she won't come at all?

I don't know.

A train.

A different world.

Dr. Seok. - Seo Kyung.

I forgot to give this back. It's your jewelry box.

Oh, right.

No one was in the office.

Did something happen?

Yesterday, Mr. Seo Jae Chul died...

in an accident.

Only Seo Jae Chul died?

Hello, I'm Han Seo Kyung from Serious Crime Team Three.

Are you in charge of the hit-and-run case that killed Seo Jae Chul?

Yes. - On route 95...

where the accident occurred,

right before the intersection where the surveillance camera is at,

there's a side road.

Here. This is the memory card from the dashcam of a car...

that was parked on that road last night.

If the victim used the side road to escape, it'll be in there.

Do you know the victim?

He's my boss' father.

Please look into it.

Back then,

what if I wasn't the detective in charge?

Do you think that would've changed things?

Where did it all go wrong?

You should go home.

You didn't get enough rest since yesterday.

Dr. Seok.

How is he still alive?

Thank you for coming.

It's you. The owner of this necklace.

I was shocked when I heard the news.

I heard it was an accident.

Yes, unfortunately.

Just a second.

Does he not recognize me?

Hello? - Sir.

They found the hit-and-run driver.

Okay, I'll be right there.

In the end, I didn't get to catch you myself,

it's not over.

I will eventually catch you.

Sir, you're here.

I'm Woo Jae Hyuk from Serious Crime Team Three.

Where's the hit-and-run driver?

Don't come near me! Go away!

My life is pretty much over.

I have no reason to live.

Calm down and put that... - Don't come near me!

Please put down the scissors.

How dare you think of dying so easily?

Let's see who wins.

Isn't that a skeleton?

Park Tae Kyung?

Mr. Seo.

Ji Young.

Isn't he Lee Ji Young's boyfriend?

This is him?

This person must be Lee Ji Young's acquaintance.

Call him.

We found this photo in Lee Ji Young's wallet...

along with the business card.

Actually, we called him a few days ago.