Competitive gamer Max (Jason Bateman) and Annie (Rachel McAdams) meet during trivia night at a bar, quickly fall in love, and get married. They are trying to have a child, but their attempts are unsuccessful due to Max's stress surrounding his feelings of inadequacy when compared to his vastly more successful, attractive brother Brooks (Kyle Chandler). During Max and Annie's routine weekend game night with their friends Ryan (Billy Magnussen), Kevin (Lamorne Morris), and his wife Michelle (Kylie Bunbury), Brooks shows up and immediately shows Max up by arriving in a Corvette Stingray and sharing an embarrassing childhood story during charades.Annie also finds Brooks extremely obnoxious and decides to work together with Max to defeat him at the upcoming game night, which Brooks offers to host at a house he's renting while visiting. Max and Annie also try to keep game nights secret from their neighbor Gary (Jesse Plemons), a humorless and awkward former police officer who stopped being regularly invited when his wife, a former friend of the couple, divorced him.When the guests arrive, including Ryan's new date, Sarah (Sharon Horgan), Brooks says he's initiated an interactive role-playing mystery game, promising the winner his Stingray. After a while, an actor playing an FBI agent informs them of the narrative of the mystery, only for two masked men to break in and assault him and Brooks. The guests, believing it to be part of the game, idly watch. After Brooks is dragged out of the house, the couples begin to solve the mystery using the clues left behind by the actor. While Kevin and Michelle play the game fairly, Max and Annie track Brooks down using his phone's GPS location, while Ryan and Sarah track down the company in charge of managing the game, hoping to find the answer there.Max and Annie track Brooks down to a seedy bar and, using a pistol left behind by Brooks during the struggle (which they believe to be fake), they manage to take the keys to the storage closet, where Brooks is being held. After Annie mistakenly fires the gun and shoots Max in the arm, confirming the legitimacy of their danger, the three escape, where Brooks admits that he actually makes his living buying and selling things on the black market, in particular a Fabergé egg sought by a man known only as the Bulgarian (Michael C. Hall) and is owned by a man using the alias Marlon Freeman. With his captors in pursuit, Brooks exits the moving car to guarantee Max and Annie's escape.Eventually, the others learn of what they've become involved in, avoiding police on one of Brooks's warnings. Trying to determine the identities of the Bulgarian and Marlon Freeman, they go to Gary's house, under the false pretense of a game night, in order to use his computer. Max finds out that Marlon Freeman is named Donald Anderton (Danny Huston) and learns of his address, though cannot find information on the Bulgarian. The group leaves Gary's house and arrives at Anderton's address, where he is hosting an underground fight club. As the others search the house, Ryan spots the egg in a safe on the wall and is caught trying to steal it. The group escapes with the egg, but accidentally break it. They discover the egg is a worthless fake but end up finding a list of names that was stored inside of it, realizing this was what the Bulgarian wanted.The group finds Brooks and his captors on an under-construction bridge and move in to rescue him. Facing execution, Brooks reveals to Max his own insecurities throughout the years as a reason for his life of crime and only wanted to be as successful as Max. Before the group gets killed, they are rescued by Gary, who is shot in the chest. Max and Annie, who have repeatedly rebuffed his requests to join them in game night, try to encourage him to pull through by promising to invite him to every future game night. Gary then reveals that he faked the entire scenario with the two captors, felons who agreed to help in exchange for a shortened parole, trying to trick them into letting him join game night again. He is, however, unaware about the egg or Brooks' involvement in it, and they are immediately attacked by the real Bulgarian, who captures Brooks after he swallows the list, revealed to be people in the witness protection program, to keep it out of his hands. Max and Annie use Brooks' Corvette (Brooks having secretly put the keys into Max's coat pocket to ensure that he won) to drive to the airport and stop the Bulgarian from taking off with Brooks in his jet. They knock the Bulgarian out and tie him up and free Brooks.A few months later, Brooks, under house arrest for his crimes, still manages to sell the list for $3 million (though also earning another $20,000 from each person on the list to let them know they've been tipped off), and Annie finally becomes pregnant. While the group (including an inept Gary) are continuing their game night, men with guns get ready to storm the building. A sequence during the closing credits reveals a diagram and models of the portion of the night that Gary had planned. In a post-credits sequence, Kenny, a man whom Michelle mistook for Denzel Washington, meets Debbie at a gas station.