I actually wrote this one up for a Big Finish short story competition afterwards, featuring the Seventh Doctor.
The Games Of Kings
A man in outdoor clothing runs full-tilt through dense moonlit woods. Another figure, in some kind of space armour, crashes through the undergrowth. A blaster flashes and cracks, flashes of light sending shadows spinning across the ground. But the hand holding the blaster is the man's. He slows his chase as the alien stumbles and raises a hand in surrender, and smirks as he fires at point blank range.
Reports filter in of strange lights in the sky over Bedfordshire. UFO sightings aren't so readily dismissed these days, but on arriving, the investigators find no-one particularly willing to discuss what they might have seen. Apparently it was a test of fireworks at the old hunting lodge owned by the Fielding family. The heir to the title, James Fielding, has restored the lodge and intends to live there, planning a party for some of his friends. At least, that's the story according to Fielding, accepted happily by some in the area and with suspicion by others.
Fielding's friends, the Boar's Head Club, are a mixture of old-money hellraisers, City money men and friends from the Army. Rich, privileged, entitled... dangerous. Some of the members had ties to Torchwood, and Fielding was among those who acquired some "misplaced" alien artefacts when the Institute fell. One of the pieces he smuggled out was a tractor beam designed to pull antigravity craft out of the sky. With that, he can bring down alien craft, seize their technology and expand his power base. With the right equipment, the Boar's Head Club could take over the world.
And the lights in the sky were the distress beacons of his latest acquisition, a scout ship belonging to the interstellar Terem Union. Fielding brought down a Terem scientific probe months ago, and the scouts looking for it suffered the same fate. So now he has a nearly-intact FTL-capable ship, and naturally he wants to celebrate. This weekend he hosts a party at the lodge, hoping to recruit more of the rich and powerful to his banner. He also plans a hunt to let the Club's strongarms try out salvaged weapons on live targets - the surviving Terem crew.
Things To Do: Infiltrate the lodge, possibly undercover during the party, discover Fielding's plans and the Club's capabilities, find a way to put a stop to them.
Antagonists: The Boar's Head Club, Fielding's thugs, and possibly the Terem unless they can persuaded that the characters are here to help.
Action Scenes: Breaking into the lodge vault, escaping the estate, rescuing the Terem, fleeing the Boar's Head hunters.
Problems: Getting in might not be as easy as flashing a piece of psychic paper. Someone with suitable connections might be able to swan in, but an apparent guest will be under closer scrutiny than someone pretending to be on the catering staff. And Fielding would regard intruders as the perfect quarry for a hunt.
Things To Prepare For: The party could be full of interesting characters, and the Club has its fair share as well, so the more you can sketch in the better. What kinds of advanced technology do the Club members have access to, besides the tractor beam and the blasters? Weapons, vehicles, armour, robotic drones? What are the grounds like? What are the Terem like, what are the surviving scouts and their ship capable of?
Continuing the Adventure: The Boar's Head Club could easily be part of a larger conspiracy, with more alien technology hidden away ready to use. Consider what Torchwood in London could have achieved without the Cybermen and Daleks getting in the way, particularly if they were only loyal to themselves...