A medical symposium! Or maybe they will have to infiltrate some high-roller criminal's dinner party to rob him of some dangerous information and keep it from being used for evil! (Goto Kasumi's plot from Mass Effect 2 )
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Actually, it could be that a criminal has stolen schematics for a Chrysalis machine and the Achenaran military contracts us to get it back for them before the information can be sold and distributed throughout the black market.