The film starts at a cabin in the woods. A couple, Shawn (Jay Pharoah) and Morgan (Yvonne Orji), have arrived ahead of their friends for a Juneteenth weekend celebration. After going through the place, they discover a board game called “The Blackening”, which features a racist caricature of black stereotypes. A voice speaks to the couple and tells them to play by asking them which horror films did not have the black characters die. Shawn incorrectly guesses Omar Epps and Jada Pinkett-Smith in “Scream 2”, where they are the first to die. The lights go out and an arrow is shot, hitting Shawn in the neck. Morgan makes a run for it but is caught by an unseen figure.
Meanwhile, another friend, Shanika (X Mayo) is at a gas station on her way to the meetup when she runs into a former schoolmate named Clifton (Jermaine Fowler), who is apparently going to the cabin as well, despite nobody remembering they invited him. Shanika is then creeped out by the gas station attendant (James Preston Rogers) who stands by her menacingly.
When the friends arrive at the cabin, they find Ranger White (Diedrich Bader) not allowing them in there without proper documents and identification, since he knows the regular owners of the cabin. After everything is settled, the friends begin to set up for partying. Nnamdi teases King for marrying a white woman before going to secretly hook up with Lisa.
The friends drink when it gets dark and begin playing games. They all question Clifton being there since none of them were really ever close with him. As the games go on, the lights go out again. The friends go to find a power box when they come across The Blackening, with game pieces correlating to their personalities. The voice speaks to them again as it is revealed that Morgan is still alive but being kept prisoner. The voice forces the friends to play the game to save Morgan, and he begins by asking trivia questions around black culture. However, the friends fail to answer all the black actors that guest-starred on “Friends”, and Morgan is attacked but manages to make a run for it. Unfortunately, she is caught.
The friends get trapped in a room where the killer makes them continue to play The Blackening. They are ordered to sacrifice one of their own based on who they deem to be “the blackest”. Each of them comes up with their own defense, such as Dewayne being gay, or arguments on who is the blackest, including Shanika saying the N-word the most or how Allison is half-black despite everyone always bringing her white half into things. Everyone ends up choosing Clifton after he admits he voted for Trump twice. Clifton goes outside and is shot in the chest with an arrow by the killer.
When the friends are free, they attempt to go look for Morgan and find help. Despite knowing better, they agree with Allison’s idea to split up. She goes off with King and Shanika while Dewayne has to go with Lisa and Nnamdi. The latter three end up running into Ranger White, who is actually willing to help them until the killer shoots him in the neck with an arrow.
Allison, King, and Shanika encounter the killer and fight him before managing to overpower and kill him. They unmask him to find that it’s the creepy clerk that Shanika saw at the gas station. Lisa, Nnamdi, and Dewayne then encounter a second killer before Lisa bashes his brains in. They look through his pockets to see that he is the twin brother of the other killer, and they deduce someone hired them to be there.
The friends go into another room where they find Clifton’s body, only for him to spring back up awake and reveal himself as the mastermind of the day’s events. His reasoning for everything was that the group always doubted his level of blackness, and after a particularly humiliating moment, Clifton drank heavily and ended up killing a woman on the road, landing him four years in prison. He organized everything as revenge and prepares to kill the others before dropping them down a well where he dumped Shawn and Morgan’s bodies. The friends fight back before kicking him down the well to his death.
As the morning arrives, the friends (reluctantly) call the police. When they arrive, the friends get sprayed with a hose.