Three months before the start of the Adventure, the PCs have been thoroughly examined and finally accepted as part of a little publicized but politically important mission.
More or less 150 people, recruited among technicians, scouts, scholars and other experienced professionals will accompany a small cadre of bureaucrats and diplomats on Rudyard, and will act as good-will ambassadors on behalf of the Imperium.
Rudyarites are good traders but they are extremely opposed to any form of government. Luckily, the Aerial Board of Control (ABC) which actually manages the entire world, has a more pragmatic view, and the Board members think that they can come to some sort of agreement with the Imperium.
The people selected for this diplomatic/trading expedition must possess good skills in various technical and/or social fields, and have been fully indoctrinated on the importance of the mission. The Imperium wants to make a good impression, so to speak, and the expedition members must be extremely careful not to anger or shock the Rudyarites. To sum it up, in the words of the expedition leader, Duchess Leonette Hautmell, "Act friendly, avoid political talk and try to project a positive, optimistic and honest attitude when dealing with the natives."
At the start of the adventure, the expedition has landed in Birha, the mayor city of the planet, where the ABC main offices are located, and things are going well enough. The negotiates have gone on for 5 weeks, and officials seems confident that in a month or so the preliminary treaties could be signed.
In the preceding weeks the PCs have encountered many Rudyarites, mostly ABC members, toured industrial plants and monuments, held seminars on their own specialties and so on. All is going well, but the mission is a little boring. The locals act friendly but remain a little aloof, and Rudyarite society is proving a little too tame by Imperial standards.
Inform the PCs that one of the ABC officers with whom they regularly interact has offered them the tickets for a sort of opera show which will premiere tomorrow night in a Birha theater.
He explains that the tickets were for the families of some of his colleagues, but the children got the flu, so his friends decided to cancel the evening out. Would the PCs like to see the show? It's actually sung in International, because the producer hopes to tour the planet with it, so they will be able to understand it, and for the premiere an extraordinary scenery has been prepared. A great show, and he just happens to have the right number of free tickets for all the PCs!

From this on, you can proceed with the adventure. Keep the following points in mind:

PC involvement

As hinted in the adventure text, the Police will be more than willing to get help on this case, which will be quite different from anything they ever had to face before.
The PCs superiors will be glad to let them take part in it, too, because this could impress the ABC and give good media coverage for the Imperial expedition.

Weapons, Violence and Technology.

Security officers will contact the PCs immediately after the incident at the theater and offer (limited) equipment and long distance assistance by radio.
Security can supply an Air Raft, some tools and no more than light personal armor (Diplo Armors for T4) and Handguns (Revolvers or Automatics). More powerful weapons could result in bad publicity, and the diplomats will insist that the PCs avoid confrontations if at all possible, and let local forces deal with the culprits, if they find them.
Remember that members of the expedition were carefully screened and selected, and even if one or more of the PCs had access to heavy weaponry (lasers obtained by mustering out benefits, for example) they will *not* have it with themselves while on Rudyard. Security can't offer more people or vehicles because they suspect that the stolen dig will be used against the expedition (which is currently lodged in a camp around the starship, parked just outside the city). All the able (wo)men, except the PCs, will remain at the starship and stand ready for terrorist attacks.
The terrorist menace is more than a red herring; it also acts as balancing tool for the adventure. If the PCs had access to 150 able bodied and competent men and women, backed by Imperial technology and with superior firepower, the adventure will be much less interesting. The need for discretion and the terrorist menace will give the referee a way to cap requests s/he considers unbalancing.

Liaison Officer

Among the public in the theater there are many ABC members. One of them will volunteer to join the PCs and act as a guide around the city. He will help them locating buildings and places from the Air-Raft. His stats are enclosed in the NPC conversion notes.