They are instead in a totally unknown system with a single inhabited planet, orbited by assorted stations and trafficked by assorted ships. There is a single, somewhat pathetic natural moon.

All the technology looks really unfamiliar and none of the communication is functioning according to any known standard; in particular, the hyperwave is dead silent. Also, about those functioning hyperdrives that, up until now, they had...

... Are now no longer functional. There's not even anything discernibly wrong with them, but their hum slowly quiets and their monitor lights all flash red.

The engineers are in a frenzy, the staff are in a panic, the soldiers are muttering to each other about the failings of Imperial Intelligence dropping them into enemy territory.

The Sith convene, visibly the calmest people in the fleet. Well, one of them. The other's just angry. But that's sort of his default, so no one notices much difference.

"Do we know what went wrong?" asks Lord Callida, immediately after she's off the shuttle that ferried her from her ship.

"I have the engineers searching for an answer, but -" Lord Nekros begins.

"- but, yes. This is not our galaxy. If it's even that. And all of the ships at once, it wasn't a single sabotage. A large scale weapon, if not something else."

"No. I'll flay those responsible alive."

"Do we have communications up yet? Talk to the planet and their fleet?"

"I didn't deem it important, the hyperdrives -"

"Well," Lord Callida says reasonably, "how can we find and flay the person responsible for this if we can't talk to the inhabited planet and find out information?"

Lord Nekros can't argue with this logic, and as such, several men are sent to figure out a communication line with the planet.

It's tough to manage, but that's what technicians are for. Within a few hours they have an open line of communication with... some people who definitely don't speak Basic, and whatever language they do speak isn't recognized by any available translation module in any computer or droid in the fleet.

Well. They have the tech to figure it out, and luckily they did actually bring a few translators. ... Translators that specialize in dead languages the tombs would be filled with, admittedly, but it's really the same thing. You know one language, you know them all, right?

...

They try to set up a holo channel as well, so they can have the computer cross reference pictures to words and have them verified. Provided the people on the other side also want to figure out language.

The comm officers on the other side (in their totally unrecognizable uniforms, surrounded by their totally unrecognizable technology) are happy to cooperate. They probably have translation software too, and it seems to be having about the same amount of trouble.

... The Imperial technicians are surprised that there are humans on the other side. They're visibly shocked and confer among themselves before they get to setting up a language-learning system. But they do get to setting up a language-learning system.

So there will be language-learning on both sides. Excellent.

Also, while all this is going on, ships from the planet occasionally travel to or from a specific part of the system, where they vanish or appear with no detectable hyperdrive signature whatsoever.

Interesting.

Lord Nekros believes that they've found a planet with some kind of hyperdrive-suppressing shield, or something that travels long distances without hyperspace at all, and he wants it.

As soon as the translators are working, he goes to introduce himself.

"Hello. I am Lord Nekros," he says. "Of the Sith Empire."

"Lieutenant Tzirakis of the Barrayaran Imperial Service speaking," says the uniformed human currently sitting at the other end of the line. "We request that you explain how you came to be in our system."

... Nekros is a little insulted that they think he'll answer to a lowly lieutenant -

"Hyperdrive malfunction, I'll have a tech on another line explain the details. I request to speak to someone in charge." Pause. "So that we can discuss the situation."

"Very well," says Lieutenant Tzirakis. "Just a moment."

The transmission cuts out. Lightspeed delay is pretty significant at this distance, so the time it takes to fetch a superior officer is actually shorter than the turnaround time between messages.

The next person on the line is wearing a slightly spiffier uniform and has slightly more impressive collar decorations. "General Vorlakial speaking," he says. "To what do we owe the pleasure of your visit, Lord Nekros?"

Nekros will have to introduce these people to hyperwave comm units, this wait is really annoying.

"We were hoping you could tell us. Our hyperdrive malfunctioned. Or, to be more precise, every hyperdrive in my fleet," because he is in command, he can call them his, "malfunctioned at the same time while we were in hyperspace, and instead of our intended destination, we arrived here."

"...'Hyperdrive' is not a recognized technology in this galaxy," says the general.

"Then what," asks Lord Nekros, "do you use to make your ships disappear?"

"Those are jumpships, entering and exiting a wormhole."

"I see. And on the other side of the wormhole is...?"

"An intermediary system on the route to the planet Komarr."

"Are there other wormholes in this system?"

"A number of dead-end routes."

"... So it's a hyperspace route," he decides, incorrectly.

"The techs don't seem to think so," says the general.

Shrug. "It functions similarly enough."

"And yet, you did not emerge from a wormhole when you unexpectedly appeared in Barrayaran space," the general reminds him. "I'm told that should have been impossible."

"The comparable fellow to hyperspace routes," grumbles Nekros, temper flaring.

"As for telling you how you got here, I'm afraid we have no idea," he continues. "Although I'm sure our techs would be happy to consult with your techs on the matter."