This is a three-player scenario. The table is rectangular, and towards one end (east) are some buildings, perhaps a farmstead. There is plenty of terrain on the table as a whole, and it really could be any setting you want, perhaps even a town. Whether or not someone can see what is going on is important in this scenario, so the terrain should contain a fair amount of sight-blocking things such as hedges and hills.
As with all games where each player is given an individual brief, it is best if they do not know the other players' briefs. The host of the game, who might know all the briefs, should play the peace-keeper (C). It is important that Player A does not know Player B's brief. Since Player A scores points for killing people, the chances that there will be no trouble at all is very slight, but after a lot of manoeuvre, it could be that the trouble consists of just a couple of shots, a scuffle, and some chases and possible arrests. The threat of violence must be countered and reacted to just as much as actual violence.
Since I am specifying no particular setting, the players and their forces will just be known as A, B, and C, but you should replace these with more atmospheric names.
Brief for Player A
You loathe your enemy, B, and wish to kill him and as many of his followers as possible. You know that Player C is going to try to keep the peace, and it would be best if you didn't start the fight when any of C's forces are looking, but this is not very important to you.
You deploy first, anywhere on the table in the eastern half.
You will score 15 points for killing B's leader figure, and 1 point for each of his followers. These are the points if you are seen by any of C's forces doing the deeds. If you can kill B's leader when C isn't able to witness this, then you get 20 points, and 2 points for each of his followers. If B's leader is arrested by the authorities and you are not, you gain 5 points.
Brief for Player B
You have to recover the deeds to your estate (or for a different setting such as sci-fi, something else of similar value), which you have hidden in a building at the far end of the table. You know exactly which building they are in and where inside it they are hidden. No one else should know that they are there, nor that you need to get them urgently, but get them you must. You would rather that you got them yourself, because the fewer people who know about this the better, and you cannot trust all of your own followers to keep their mouths shut.
You have problems, though. Your enemy, A, has come to cause trouble, and is between you and the deeds. Also, the authorities, player C is monitoring the situation, and has a force of armed men to keep the peace. You are on your own land, though, and the authorities have no right to throw you off it, nor to arrest you if you do not commit violence.
You deploy last, entering from the western end of the table.
You get twenty points for picking up the deeds personally, and fifteen if an underling of yours does it for you. For each man you lose, you lose a point, and if you are wounded you lose three points. You lose the game if you die. Also, if you kill an enemy man while none of Player C's forces can see you do this, you score one point. If A's leader is arrested and you are not, you gain 5 points. You total up your score when you leave the table.
Brief for Player C
You represent the local authorities. You are there to keep the peace and to witness any crimes so that prosecutions can be made at a later date. If you are watching, then no one should try anything, but you are familiar with the ways of the locals, and they are quite likely to try and murder each other when your back is turned.
You deploy second, anywhere on the table. Player B will be entering from the western end.
If trouble starts, you must arrest the leaders of the factions and get them off-table. Once you have arrested a man, you are responsible for his safety.
For each man you lose, you lose 2 points, for each wounded, one point. If you are able to keep the peace enough such that no one gets killed, you get 10 points. If a fight does break out and you witness who started it, you get 5 points. If, after trouble starts, you arrest one of the leaders, you get 10 points. If you are able to arrest both leaders, you get 25 points. For each other man arrested whom you witnessed committing a crime, you score 1 point. You score these points as you get the men alive off-table. However, if a leader in your custody is wounded, you lose 5 points, and lose one point for other men wounded.
The players A and B must think of themselves as being their leader figures. They can escape arrest by simply leaving the table, but in their absence, their forces will just leave as well. They must be on the table to command their forces. If leader A or B dies, then that player loses regardless of all other results.
A violent crime has been witnessed if any of C's men have line of sight to both killer and victim at the time of the assault. If only one of the two is seen at this moment, then this is less good evidence in court, and will only count half the time (so roll a die to see if this counts as being witnessed by C).
A leader should not be able to lead his men by remote control. If your rules system has no rules for command, then you will need to introduce some, otherwise a player might place his leader hidden behind a hedge in one corner of the table, and micro-manage his minions from there, which is not in the spirit of the game. You could rule that point-scoring events involving the enemy leader (he gets arrested, killed, whatever) are halved if not witnessed by a player's leader figure from within a certain distance (half the width of the table, perhaps), to encourage players to make their leaders part of the action.
Leaders can communicate with each other to offer deals, threats, ultimata etc. so long as they are within line of sight and two-thirds of the table's width or less apart, or out of line of sight and less than four inches apart. The distances are small and shouting will usually do the job.
A leader can freely offer himself for arrest. If Player C has not witnessed his forces committing any crime, no points are lost or scored for this, and he is now under the protection of Player C. Under certain circumstances, this could be a game-winning move.
To arrest a leader against his will, Player C must get at least two men to within arm's reach of him, and then have at least two of his men win their combat with him in the same turn. One man fends off the leader's weapon, while the other(s) grab(s) him.
Player A should have a moderately good leader, and a few decent troops, and a load of poor troops. Total perhaps 20-30 men.
Player B should have a moderately good leader, and fewer men than A, but a greater proportion of them as decent troops. Total perhaps 15-20 men.
Player C should have a very good leader, and a force smaller than both A and B, but made up of better quality troops than both. Total perhaps 10-15 men.