From the introduction:
In this adventure, two of the campaign variants of STAR TREK: The Role Playing Game are brought together, involving both Star Fleet officers and independent merchants as player characters. Each group has come to the Orion-colonized world of Daros IV on an important mission, but whereas the merchant characters see Daros as a world of golden opportunity, the Star Fleet characters have a much lower opinion of the planet and its inhabitants. Much of the entertainment and excitement in this scenario should come as the two sets of characters, with differing skills and very different goals, attempt to complete their missions without causing each other complete disaster. The gamemaster will need a copy of FASA's merchant supplement, Trader Captains and Merchant Princes, in order to run the adventure successfully.
The Orion Ruse is intended for a group of two to ten players.