Await Further Instructions

Nick travels to the home of his estranged parents, Tony and Beth, to spend Christmas there and introduce the family to his girlfriend Annji. His pregnant sister Kate, her husband Scott, and his grandfather are also there. Tensions arise after Kate and the grandfather make racist remarks to Annji, who is of Indian descent.
The family members quickly find that they are surrounded by a strange black substance and that they cannot leave the home. They receive messages warning that their food is contaminated and instructing them to cleanse themselves with bleach and take vaccines dropped down their chimney. Annji is suspicious of the vaccines as the syringes look used, but Tony forces everyone to inject them. The grandfather suddenly vomits a black liquid and dies.
The living room television shows lines of text claiming one of them is infected. Believing Annji is infected, despite Nick's protests, the rest of the family lock her in a bedroom with the grandfather's corpse. Kate urges Scott to attack Nick, but she is injured in the chaos. Trying to find an escape, Nick locks himself in a room, attaches his phone to a long stick and uses it to record the view outside the house, capturing footage of a snake-like creature.
Prompted by the television, Tony and Scott rush in, knock Nick unconscious, and drag him downstairs. The television tells them that Nick is a spy and that they must get information from him. Tony refuses to look at the phone footage and tortures Nick until Beth interrupts them to let them know that Kate has died.
The surviving family members are told to return to the first floor as the television is activating quarantine. Nick is able to get Annji downstairs but is unable to save Beth, who dies after being exposed to a mysterious black smoke. Nick and Annji rush downstairs to find the television shining a bright light. Even as Nick unplugs it, the light stays on and the house begins shaking. The television proclaims that it is being "resurrected" just before Nick passes out.
Nick awakens to find that himself and Annji restrained, to be sacrificed. Tony attempts to kill Annji with an axe but Nick and Scott stop him. Tony murders Scott with the axe. After a brief fight, Nick crushes his Tony's head with the television. Black wires crawl out of the television and enter Tony's head, taking control of his corpse.
Nick and Annji realize that the black substance is composed entirely of the living wires. Nick destroys the television, only to learn the wires can survive without it. Tony, being controlled by the wires, kills Nick and Annji with the axe. The wires digest Kate's body, leaving only her skeletal remains and her newborn baby.
Tony brings in another television, which names the baby "Ruby." It displays colourful patterns to get Ruby's attention before changing to text that says "worship me". Outside, it is revealed that every single house has been wrapped in the same black wires.