Plot

Four friends are murdered in their own home for no reason by four members of the Manson Family.

Four friends gather at an elegant home during the Summer of Love, 1969. Unbeknownst to them, deadly visitors are waiting outside. What begins as a simple farewell party turns to a night of primal terror. The intruders stalk and torment the four, who struggle for their lives against what appears to be an attack by a Manson Family type group.—Warner Bros.

The movie begins with an older married couple sleeping in bed and are awaken by knocks on their doors and windows. The husband goes downstairs to investigate but finds nothing. As he gets back into bed, he hears a crash downstairs. He sees the shadow of a man saying "Little Pig". As he runs back to his room to his wife, he locks the door. The intruders shake and band on the door until it opens. It cuts to a police officer entering the house.

The movie then goes to 4 friends at a restaurant celebrating their friend Abigail's birthday and going away party. The friends, Sharon, Jay, Wojciech, and Abigail return to Sharon's house. A pregnant Sharon calls her husband from the nursery, but suddenly the line goes dead. Meanwhile, someone is visiting the guest house to sell the occupant a stereo. As he leaves, the gate in the driveway doesn't work. He gets out and opens the gate, but his vehicle turns off unexpectedly. As he returns to his vehicle, he turns his headlights on to see a man standing in front of his truck and a woman standing behind his truck. He is then pulled out of his truck.

Wojciech goes outside to have a cigarette. As he approaches the truck in the driveway, he sees a man slumped over. He asked the man if he is alright, but the man lunges at him and chases him to the front door which is locked. Later, we see the front door say "Pig" written in blood.

Sharon and Abigail are talking in her bedroom when they hear Jay screaming and moaning from the living room couch. When they investigate, they discover he has been stabbed to death. They try to hide throughout the house as the intruders stalk them. Sharon and Wojciech are seen dragged through the hallway as Abigail escapes the house. She tries to get help from the man living in the guesthouse, but he has his headphones on and can't hear her. One of the intruders catches Abigail and carries her to the house.

The intruders continue to torture and torment the 3 remaining friends as they hunt them down one by one.

At the end of the movie, it shows interviews of Manson and some of the attackers involved in this story.