PCs receive SOS signal from the small, private yacht. Message contains information that three passengers have been terrorized by a madman. He is armed with a handgun and had damaged vessel's cockpit.
Yacht's engines are shut down so docking should be no problem. Airlock is not locked so sneaking on board should be rather easy, of course if docking was done properly (i.e. without ramming the yacht!).
Yacht's crew consists of two males and one female. They look like rich men, travelling for pleasure. "Terrorist" is a young man, apparently a pilot. He is armed with heavy pistol. He shouts something about aliens pretending to be humans, impersonating his friends. His movements are uncoordinated and he has restless eyes, as if he is on some kind of drugs.
Even if PCs want to negotiate, it's highly possible that sooner or later he will attack, but his primary target will be his hostages. Even then, his attack will be extremely uncoordinated and disarming him will be rather simple task (killing him may be even simpler).
After the fight, passengers will calm down really fast. If asked, they will tell that Mark's behavior (pilot's name) was rather strange during the whole cruise. In the past they suspected him to be a drug addict but they never thought that it will lead him that far. They also ask PCs if they can repair the cockpit, shot dead by Mark, as no one of them is able to do it.
The only problem is that Mark was telling the truth - real owners of the yacht were killed and replaced by aliens capable to mimic humans. They will try to drug PCs with psychoactive substances (the same drugs that they previously gave Mark), in example in snacks, cigarettes or wine. Later, they will use their disgusting, violet ovipositors to get through PCs' nasal cavities to their brains and lay eggs there.
Aliens are armed with small, concealable handguns, hidden in ship's safe. Despite size of the weapons, they are apparently alien-made, so their real firepower or exact methods of attack may be not that certain.
Aaand yacht's stats for Terminal Space and Bandits & Battlecruisers:
Hull Type: LF (8 Structure Points, Pilot skill mod +5%)
Armor: ceramite (25)
Drive Class: C
Maneuvering Thrusters: two additional units
Jump Drive: none
Sensors: civilian +10%
Jamming Systems: none
Armament: two light lasers in automated turrets
Shield Generator: none
Cargo Space: 5t
Other: luxury passenger apartments, jacuzzi, sauna, small gym, communicator systems in passenger cabins, automated docking system, expensive civilian jetbike in cargo hold.
Sorry for this rather new-school adventure plot, but it was written by me over two years ago, especially for this entry of my random table. Oh, and graphics above is a wallpaper from the awesome Transcendence game.