A Game Concept in Search of a System

[Amphetryon]

The city has always run this way: 5 masked council members, their physiques cloaked in robes and magic for additional anonymity, knowing that their anonymity allows them to behave as the city needs, rather than as their friends - or enemies - would prefer in the short term. Now, however, evidence is mounting that one of the council members has been discovered, and has been bribed. . . .

Basically, the idea is that the majority of the Players represent honest, anonymous members of the council, while one of them plays as a bribed or blackmailed member, trying to advance the agenda of unmasking the other council members and thus undoing the political system.

Do you know a game system that would support this type of setup?

[CombatOwl]

The city has always run this way: 5 masked council members, their physiques cloaked in robes and magic for additional anonymity, knowing that their anonymity allows them to behave as the city needs, rather than as their friends - or enemies - would prefer in the short term. Now, however, evidence is mounting that one of the council members has been discovered, and has been bribed. . . .

Basically, the idea is that the majority of the Players represent honest, anonymous members of the council, while one of them plays as a bribed or blackmailed member, trying to advance the agenda of unmasking the other council members and thus undoing the political system.

Do you know a game system that would support this type of setup?

Fate. Definitely Fate. Literally, it has a system for handling that. The bribed/blackmailed member should have an aspect to that effect. Make everyone keep their aspects secret, only allow one player to discover another player's aspects through social conflict concessions. This forces the party to start arranging plots to force concessions out of other characters, engaging in elaborate and drawn out social conflicts. They would even have reason to go digging around in people's lives, looking for evidence (which is easily modeled as an aspect), which they can later tag for bonuses in the aforementioned social conflicts. Let people refer to their aspects by number or letter so as to preserve mystery. It has a nuanced system for doing social "combat" that is quite good.

All of the side things--combat, assassination plots, skulking around, etc--are also handled well by Fate.

It's the same way a murder mystery works with Fate.