WARNING: The following contains spoilers for Werewolves Within, now in theaters and available on video-on-demand.

Werewolves Within is a horror-comedy movie with snappy editing, acting and writing, set in the small town of Beaverfield, Vermont. Forest ranger Finn Wheeler arrives only a day before it's sealed off from the outside world via snowstorm and has to prevent its quirky residents from tearing each other apart amid fears of a killer hidden among them. That's a great premise for a horror movie, but also fairly recognizable to anyone who's played enough tabletop games.

It's the exact setup for a hidden-role game, in which players have to deduce which of them is secretly a murderer before they run out of time. This is because Werewolves Within is directly based on a Ubisoft game of the same name. The original Werewolves Within is a VR social deduction game, where players try to figure out who among them is the "werewolf." The game adds an interesting twist by presenting the game through a shared virtual space, but is a fairly straightforward translation of the folk game "Werewolf," also referred to as "Mafia."

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What Is Werewolf?

Originally developed under the name "Mafia" by Russian professor Dimitry Davidoff, the game runs on a simple premise and requires no specialized pieces or boards to play. Each player is secretly assigned a role -- either Villager or Werewolf -- and the game then runs in two phases, night and day. During the night phase, the werewolves open their eyes while the rest of the players keep theirs closed and silently select a player to "kill," removing them from the game. After that point, all players open their eyes and, using only the clue of who was killed, try to deduce who the werewolf is. The day phase ends with the villagers voting to kill one of their own. This pattern of day to night to day repeats until either the villagers find and kill all the werewolves, or the werewolves kill all the villagers.

While the rules of the game are simple, its value lies primarily in its social nature. "Perfect players" of the game are rare, and individual games vary wildly depending on the strategy of the participants and their relationship to one another. Strategy in the game is often not about analyzing the situation to its fullest (like in chess) but instead being able to read the other players involved. It's also a highly adaptable game, as its few rules and easy setup make it easy to modify. Players can alter the number of werewolves, add new roles like "Detective" or "Hunter," or even change the turn structure.

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How Werewolves Within Compares to Werewolf

An ensemble shot of the cast of "Werewolves Within"

Werewolves Within takes the fictional premise of the game Werewolf (villagers must distinguish who among them is the Werewolf) and uses it to build an atmosphere of fear and suspicion. The audience is introduced to the town through the eyes of newcomer Finn, and quickly meets Beaverfield's colorful cast. It's also swiftly established that the townspeople have plenty of existing qualms with each other. The proposal of a new pipeline along with a huge payout is a fierce subject of debate, which only exacerbates existing political differences. The discovery of a corpse and the implied threat of a murderer feels very much like Werewolf's first "day phase," as most of the time is spent simply establishing the groundwork for everything yet to come.

Those accusations aren't enough to escalate to action until the second "night phase," when the werewolf bites off Pete Anderton's hand. But after that, it becomes open season, as the townspeople use the lawless atmosphere as an excuse for violence. That's the biggest difference between Werewolves Within and its inspiration: The movie isn't about people trying to act rationally to win a game. Instead, they are vicious, spiteful and do far more damage to each other than the werewolf does. Overall, the werewolf is only directly responsible for two of the film's 10 deaths (counting poor Chi-Chi the dog). The rest are brutal murders, borne of fear, resentment and revenge. It's only Finn's cool attitude that saves the day, along with the quality that makes him such a good forest ranger -- a commitment to civic duty, respect and kindness.

Werewolves Within is directed by Josh Ruben and stars Sam Richardson, Milana Vayntrub, George Basil, Sarah Burns, Michael Chernus, Catherine Curtain, Wayne Duvall, Harvey Guillén, Rebecca Henderson, Cheyenne Jackson, Michaela Watkins and Glenn Fleshler. It's available for purchase through Amazon Video, iTunes or Google Play.

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