A woman known only as "The Neighbor" lures a man to her secluded woodland home. Drugged, the man stumbles outside to a car. Clad in a welding mask and protective suit, the neighbor shoots out the car window with a shotgun, allowing a zombie to climb inside and eat the man.Teenager Jason leaves behind his arguing parents to go on a cabin retreat with his best friend Colin, Colin's father Roger, Roger's girlfriend Lisa, and Colin's sister Summer, whom Jason has a crush on. The group stops at a café where Jason briefly observes the neighbor interacting with two drunken young men.While Roger and Lisa remain at the cabin getting drunk together, the three teens explore the woods. Jason, Colin, and Summer come upon the neighbor's house, where they find several cars parked outside covered in black goo, as well as a barrel full of melted personal items. The trio hides when the neighbor returns home with the two young men from the café.From outside, the three teens spy on the other trio. Jason, Colin, and Summer are shocked when they see the two men collapse after drinking drugged wine. They then flee when Colin and Summer see the neighbor feeding the men to her two captive zombie children Quentin and Alicia.Colin impulsively throws a rock that breaks a car window. The neighbor comes outside to investigate the noise and seemingly spots the three teens as they race back to their cabin.Jason, Colin, and Summer frantically try to explain what they saw to Roger, who is too drunk to take their claims seriously. Roger instead takes an ax from Jason and decides to investigate the alleged cannibalism for himself. Colin stays behind with Lisa while Jason and Summer accompany Roger.Roger, Jason, and Summer explore the neighbor's house, but find it empty. Meanwhile, the neighbor comes to the other cabin and unleashes her zombie husband Harold. Harold devours Lisa while Colin is in the bathroom.Roger drinks drugged wine left out on a table and falls unconscious. Unable to carry him, Jason and Summer look for a place to safely stash Roger. Jason opens a floorboard hatch but, because of the smell from the room below, decides to put Roger in a closet under the stairs instead.Another closet door rattles. Summer opens it and Jason immediately swings his ax, only to find that the person on the other side is a bound and gagged prisoner. Gushing blood, the duct-taped man hops into a hallway. A zombie suddenly tackles and begins eating the man. The zombie turns its attention toward the teens, but falls into the floorboard hatch.The duct-taped man turns into a zombie. Jason and Summer throw him down the hatch too.Jason and Summer hide from the neighbor and her zombie husband when they cross paths in the forest. Jason and Summer return to their cabin, where they discover Lisa transforming into a zombie. While the two of them impale Lisa with a fireplace poker, Colin blows Lisa's head apart with a shotgun.Jason is compelled to tell the siblings that he lies about where he lives because his parents are wealthy, but he is ashamed of their incessant bickering. Jason mentions how envious he is of the love that Roger, Colin, and Summer have as a family despite how much they tease and prank each other.Resolving to rescue Roger, the three teens suit up and arm themselves with items from an equipment shed. When they arrive at the other cabin, the neighbor releases several zombies to attack. Jason, Colin, and Summer fight their way inside.The two zombie children break out of their locked room and shamble down the hallway. At the same time, Roger recovers and exits the stairway closet. While Roger has a heart-to-heart moment with Colin, Jason and Summer kill the zombie kids.The neighbor returns and is horrified to see her children dead. Roger fights the neighbor, who gravely wounds Roger before retreating outside. The three teens begin escorting Roger to a car, but the neighbor reappears and kills Roger with a shotgun blast from behind.Jason, Colin, and Summer scatter in the ensuing commotion. The neighbor begins stalking Summer. Jason suddenly runs over the neighbor with a truck. Colin then uses a sledgehammer to crush the neighbor's head as she continues taunting the teens while dying on the ground.Jason, Colin, and Summer collect Roger's body and drive away in a truck. Jason takes a call from his parents on his cellphone.