In short, One Night Werewolf is a spin-off of the familiar game of Werewolf (a.k.a. Mafia) in which players secretly divide into teams based on character cards they're dealt, then play through alternating night and day phases, with the werewolves deciding to eat one villager during the night, then the villagers (which include the werewolves in human form) argue over who to lynch the next day to save their town. In One Night Werewolf, the game lasts only a single night, with a few characters taking a role (the werewolves see one another, the seer looks at one character card or two cards out of play), then everyone simultaneously voting on who to kill. If they kill a werewolf, the villagers win; if not, the werewolves win.
One Night Ultimate Werewolf, a co-design between Okui and Bézier's Ted Alspach, adds many more character roles to the game, giving players more to do than being villagers and consequently more to argue about in the subsequent morning. Says Alspach, "It's a microgame that thinks it's a regular game." In more detail from Alspach:
One role card is dealt to each player, and three additional role cards are placed face down in the center of the table. After everyone secretly looks at their cards, they close their eyes, and the night phase begins.
Werewolves see the other werewolves. The Seer can view one other player's card. Nothing earth-shattering there...so far it's pretty much regular werewolf, right?
But then the other roles take their turn at night: The Robber steals someone else's card and becomes the role he steals. The Troublemaker switches two other player's cards. The Doppelgänger looks at another player's card and becomes that role. The Minion learns who the werewolves are (he's on their team). And a whole bunch of other roles.
The night phase is over, players open their eyes, and may say anything they want. They are trying to figure out who the werewolves are. After a few minutes, everyone votes simultaneously: If a werewolf dies the villagers win; if a werewolf doesn't die, the werewolves win. Easy, right?
But here's the catch: Players can't look at their card. Remember the Robber and the Troublemaker? Well, they know what they did last night, but odds are they aren't going to fess up to it...so you'll have to deduce not only what the roles of other players are, but you may not be your original role.
There's another catch: Remember those three cards in the center? There's a chance that the werewolves are in those center cards, which means the only way players can win is by not killing anyone, which they pretty much all need to agree to. If a player dies when the werewolves are in the center, everyone loses.
The replayability is off-the-charts, with thousands of scenarios thanks to all the different role cards (12 different roles) and how the cards can be dealt out.
A bit more from Alspach: "The last time I've been this obsessed about a game was when I was playtesting Dominion, and we were testing the base game, Intrigue, Seaside and Prosperity back-to-back. I racked up 300+ playtester plays in the course of several months. One Night Ultimate Werewolf has done that one better: I've played more than 400 games since early June when we started to develop it. Not only that, but I love to watch other people play too. Thank God I had my actual Essen releases pretty much in the bag before I started on this..."
Alspach plans to release a free iOS/Android app to help players run through the character role call each night for while you don't need a moderator for the game, someone does need to call out the characters in a particular order so that they can take their actions, and the app recalls which characters are in the game and presents them to you in the proper order.
One Night Ultimate Werewolf is available for demo games at Spiel 2013, and will be released in January 2014. Bézier plans to run a one-night Kickstarter project (how thematic!) for this game on October 29, 2013. Says Alspach, "The games should be produced by then, and this is for pulling some out of the main ship-based shipment and air-freighting them over to the U.S. for (1) hand delivery to BGG.CON 2013 attendees and (2) other people who want to get a copy as soon as possible."
I played once at Spiel 2013 yesterday, and while I normally stink at bluffing/role games, I somehow managed to wind up on the winning team, but thanks only to someone switching me away from being a werewolf so that I didn't have to pretend anything. Phew!