Assemble a group of players. An odd number is best, although not absolutely mandatory. There should be at least seven players.
You should have an equal number of cards to the people playing. You should always have 1 Seer, 1 Doctor, and 2 werewolves and the rest of the players should be Villagers. If you have a large group (16+), you can replace a Villager for an additional Werewolf.
Shuffle the cards and hand them out, face down. Each player should look at their card, but must keep it a secret. You can learn more about what each character can do here.
The game proceeds in alternating night and day rounds. Begin with nighttime.
At night, the moderator tells all the players "Close your eyes." Everyone begins slapping their knees (or table) to cover up any noises of the night.
The moderator says "Werewolves, open your eyes." The werewolves do so, and look around to recognize each other. The moderator should also note who the werewolves are.
The moderator says "Werewolves, pick someone to kill." The werewolves silently agree on one villager (It's critical that they remain silent). The other players are sitting there with their eyes closed, and the werewolves don't want to give themselves away. Sign language is appropriate, or just pointing, nodding, raising eyebrows, and so on.
When the werewolves have agreed on a victim, and the moderator understands who they picked, the moderator says "Werewolves, close your eyes."
Now, the moderator awakens the Doctor and says, "Doctor, who would you like to heal?" The Doctor selects someone they'd like to heal. The person chosen (which could be the Doctor himself) will survive if the werewolves had chosen to kill them. If someone was killed, and then saved by the Doctor, the moderator will let the village know by saying, "Someone has been saved", at the beginning of day time.
The moderator says "Seer, open your eyes. Seer, pick someone to ask about." The seer opens their eyes and silently points at another player. (Again, it is critical that this be entirely silent -- because the seer doesn't want to reveal his identity to the werewolves.)
The moderator silently signs thumbs-up if the seer pointed at a werewolf, and thumbs-down if the seer pointed at an innocent villager. The moderator then says "Seer, close your eyes."
The moderator says "Everybody open your eyes; it's daytime. And let's the villager know who has been killed. That person is immediately dead and out of the game. They do not reveal their identity.
Alternative rule: After you die, you reveal what role you had.
For the first day, go around and have everyone introduce themselves (Example: Hey, I'm Matt. I'm the baker here in town, and I'm a villager.
Daytime is very simple; all the living players gather in the village and decide who to lynch. As soon as a majority of players vote for a particular player to lynch, the moderator says "Ok, you're dead."
Alternative rule: To keep the game moving along, you can put a time limit to how long a day is, and if the village doesn't chose someone to lynch, they miss the opportunity.
There are no restrictions on speech. Any living player can say anything they want -- truth, misdirection, nonsense, or a barefaced lie. Dead players may not speak at all. Similarly, as soon as a majority vote indicates that a player has been lynched, they are dead. If they want to protest his innocence or reveal some information (like the seer's visions), they must to do it before the vote goes through.
Once a player is lynched, night falls and the cycle repeats.
Moderator note: Continue to wake up the Doctor and Seer even if they are no longer alive.
The villagers win if they kill both werewolves.
The werewolves win if they kill enough villagers so that the numbers are even. (Example: Two werewolves and two humans)