The Japanese trial involves a case that Ryuunosuke found himself caught up in three days prior. Meanwhile, the scene with Holmes and Ryuunosuke investigating the Russian man takes place on board a steamship.

All the exclusive footage is shown in a small theater, which you'll need to get (free) tickets for.

First the TGS promotion video is shown. Then gameplay footage. Part of it was already shown in the Special Stage. There was also a bit of the Japanese court. Ryuunosuke introduces himself as a second year university student and says he's in court because of an incident that happened three days earlier. His opponent was a prosecutor who looked like Payne. His "objection" voice was also Payne-like.

Finally, the Special Court is fully voiced promotion video like previous Special Courts, using ingame assets.

Ryuunosuke and Susato appear in the English court "because of DGS which is planned for a 2015 release"(screenshot 1). Then Holmes appears, who upon seeing Ryuunosuke blurts out "But aren't you that dead Italian head cook?!" (See screenshot. He's dead! But this will be explained later).

Holmes thinks that Ryuunosuke was the Italian head cook because of a certain telegram. The contents of that telegram? The truth behind this case? That's what the Special Court is about.

There's a secret to the telegram, but the story is mostly about Holmes' silly mistakes.

As for how the characters appeared:
Holmes -> Natural airhead. Might describe him as a "clean Luke Atmey"
Susato -> Active, but can be a bit silly too.
Ryuunosuke -> Comments on and corrects both of them

Holmes also makes a comical meta-comment at the very end, which is very Takumi-like apparently.

Like Olivia Aldente? The PLvsAA influence is truly strong with this one.

12:39

Aboard the steamship "Prussia"
Special Guest Apartments, Lodge No. 2

Holmes: Actually... Just by looking, I knew he was the suspicious-looking Russian man pictured.
...Mr. Naruhodou, I've been thinking about this from time to time.
Is it because he is Russian that he is suspicious... or because he is suspicious that he is Russian?
Naruhodo: ...I don't think it's either.
Holmes: Just now, I've come upon the "conclusion"... There are no other possibilities.
Well, Mr. Suspicious Russian, sir. My "conclusion"... is but one at the moment.
Loylot: W... what!?
Holmes: Your "true identity"... is an extremely dangerous "revolutionary"!
...Furthermore.
With those scissors... you had just snipped off the "life" of something rather precious...
Am I wrong?
Loylot: Ah...!
Holmes: ...Very well. Shall we discuss the reasoning behind this in detail?
Of Sherlock Holmes' "famous deductions"...!

Reasoning Start
The game is afoot!

Topic 1
The elderly man's true identity

Holmes: Now then, I will begin my brilliant deductions.
Regarding this clearly suspicious Russian man's identity...
First, what's important to note is, of course...
the large scissors that would catch anyone's line of sight. [!]
Just what was he intending to do with them?
The answer is... something that would be made clear upon "observing" you.
You used those scissors to snip off that impressive beard! [?]

Now, let us move to the next point.
About that well groomed beard... why would you suddenly decide to cut it...?
Here, I have the morning's "paper" with a noteworthy article written.
...It appears you have also read the same "news".
Do you see now?
It is the "evidence" that points out your true identity... the article on the revolutionary! [?]
"The famous revolutionary from Russia, Demetri Demiglace, has fled in exile"...
And pictured in the photo... is that often conspicuous beard.
Having read the article, you cut your beard to avoid being noticed by others aboard the ship.
...Therefore, your "true identity" has been made clear.
You, my bearded acquaintance*, are none other than the dreadful revolutionary... Demetri Demiglace!
...Well, I haven't heard very much, so I'm not completely sure.

Conclusion
Russian revolutionary

Naruhodo: ...Uh, Susato? Was that one of the rumored "famous deductions" of his?
Susato: Um, yes... I have read about them in his stories...
But the "famous deduction" just now... it seems to have the wrong air about it.
Naruhodo: Hey, Mr. Holmes, could you come over here?
Holmes: Ah, Mr. Naruhodou, what seems to be the matter?
Naruhodo: That reasoning just now... seems a little odd.
Holmes: Mm... what of it?
Naruhodo: Um, about this Russian man...
He looks nothing like that dreadful revolutionary!
Holmes: Well... in any case, he's somehow related to that dreadful revolutionary.
Perhaps, he was able to "revolutionize" his face.
Susato: Hmm... that certainly is dreadful...
Naruhodo: (Ugh... you got to be kidding me.)
Susato: Anyway, Sir Naruhodou, about Sir Holmes' "theory"...
There may be merely minor errors in certain "viewpoints".
The key to Sir Holmes' "theory" lies in some important "comments".
May we secretly exchange them with others?
Naruhodo: (...Geez, what a troublesome "Great Detective"...)
Holmes: Ah, I seem to have laid trouble on you, my friend! Ahahahaha!
Naruhodo: (...What's with the haughty laughter?)
Holmes: Then, let us begin. This time, following the genuine path to the truth.
Of Sherlock Holmes' "famous deductions"...!

Analysis Start
Hold it, Mr. Holmes!

Topic 1
The elderly man's true identity

...
Holmes: You used those scissors to snip off that impressive beard! [?]

[lower screen]
Susato: Hmm... so did he use those scissors to cut that beard?
Naruhodo: It looks like the Russian man didn't get quite the same idea.
Susato: Then... let us exchange this comment at once!
What sort of thing did the man actually cut off...?
Naruhodo: Anyhow, though it may be rude, let's "analyze" it!

[examine "impressive beard"]
Naruhodo: That sure is an impressive beard.
Susato: To us, one's hair does have a certain "life" to it.
But to the elderly Russian sir, does he treat it as his "life"?
Naruhodo: Uh, not that I'd know.
I'm no Russian or elder.

[examine "thick coat"]
Susato: It appears to be a very warm outer garment.
Naruhodo: No matter how you put it, Russia is a very cold country, after all.
Susato: ...Yet, it's rather warm inside this ship.
Naruhodo: That means! Since he was too warm, he cut off some parts of his coat!
Susato: If it was me, I would simply unbutton the coat.
Naruhodo: Well, you have a point.

[examine "beautiful golden hair"]
Susato: My... what pretty "hair" he has!
Naruhodo: That is, "hair" atop his head.** It sure does have a nice golden shine.
But why does he have golden hair at the back here?
Susato: Pretty golden hair peeking out from that stocky black hair...
Naruhodo: (This is definitely suspicious...!)

Take that!
[beautiful golden hair]

Naruhodo: You used those scissors to snip off that beautiful golden hair!
Holmes: That's right... that is exactly what I was saying!
That slender hair... unfortunately, I doubt that would belong to an elderly man.
...

21:58

Take that!
[Dancing Girl Article]

Naruhodo: It is the "evidence" that points out your true identity... and that is...
Holmes: It seems I finally am able to announce your real name.
Naruhodo: And that is...
Holmes: *bleep* , isn't that right?

Conclusion
Russian revolutionary
*bleep*

[SOLVED]

* Using 'koso' after a subject puts emphasis on the subject. I might as well add a little decoration.
** Susato uses 'ogushi', the honorific form of 'kami' ("hair"), written in kana. It's rarely heard this these days, so Naruhodo makes a note of it for the audience. Nonetheless, veterans of traditional-style Japanese movies will occasionally hear of its usage.