Plot

A teenage girl and her younger brother must survive a wild 24 hours during which a mass hysteria of unknown origin causes parents to turn violently on their own kids.

Something terrible is definitely happening in the a peaceful suburban community as, day by day, former caring parents mysteriously turn into ravenous carriers of an unfathomable pandemic that targets their offspring. Suddenly, like every son and daughter in the entire nation, teenage Carly and Josh Ryan must run for their lives, as the rage-filled murderous intent is as unstoppable as it is inexplicable. Before long, the Ryans' usual simmering familial tensions take on a completely different meaning. Kids, stop hiding. Mom and Dad love you so much.—Nick Riganas

The Ryans are the typical dysfunctional family from any suburb: troubled teen Carly thinks only of herself, her woes, and her new boyfriend Damon and doesn't get along with her younger brother Josh; full-time mom Kendall feels desperately that her youthful dreams are gone and her relationship with Carly isn't what it should be; and dad Brent is a CEO who lives in eternal self-disappointment and dreads his parents' upcoming visit. The Ryans' rut abruptly ends one day when without apparent reason, first along their suburb and gradually throughout the country, loving parents turn homicidal on their own offspring. Several parents pursue and kill their children in a bloody slaughter right at their own school. Carly and her best friend Riley escape from the hysterical mob of killer parents, but when they get to Riley's house, Riley's mom is there and kills her daughter, and Carly just barely escapes, helped at the last minute by Damon. They both hurry to Carly's house, where they discover that Kendall and Brent have gotten home early with just one idea in mind: kill their kids at any cost.—Chockys

The film opens with a mother putting on soothing music for her child as she sets her car on railroad tracks and leaves the child in the car to die.

Then, we are introduced to the Ryans. They are a family of four with a strained relationship. Brent (Nicolas Cage), the father, does not approve of his teenage daughter Carly's (Annie Winters) new boyfriend; Carly is angry with him, as well as her mother, Kendall (Selma Blair), whom she considers out of touch. Carly also fights with her much younger brother, Josh (Zackary Arthur), who annoys her. Carly is forced to cancel plans with her boyfriend, Damon (Robert T. Cunningham), for dinner with her visiting grandparents.

As Carly is at school, an unexplained static starts transmitting through all TV screens and radios. The effect is seen as the Ryans' housekeeper murders her own daughter with a meat tenderizer in front of a terrified Josh. Suddenly, a mob of parents rushes Carly's school in an effort to kill their children by any means they can. Carly escapes the school with her best friend Riley (Olivia Crocicchia) and hides out at her house, where Riley's mom attacks and strangles Riley to death. Carly runs home in terror, running into Damon - who has killed his own father in self-defense. Damon tells Carly that the parents appear intent on only wanting want to kill their own kids but not other people, and accompanies her home to get Josh somewhere safe.

After an exercise class, Kendall goes to the hospital to be present for her younger sister Jenna's (Samantha Lemole) baby, but the static transmits just after Jenna gives birth, causing her to attempt to kill her baby. Kendall escapes from the hospital, seeing reports of the mass hysteria on television - the static gives parents a natural instinct to slaughter their children. In an effort to protect her own children, Kendall heads home. Brent heads home as well, as he is bored at work.

Upon seeing Carly with Damon at home, the hysteria fully overtakes Brent, and he knocks Damon out and attacks Carly. Kendall joins him upon getting home; having been infected by the signal through her car radio. Carly and Josh escape them and lock themselves in the basement. Kendall and Brent bond over their shared desire to kill their children, and run a hose from their oven's gas pump to the basement in an effort to poison the kids. When Carly sees the gas, she rigs up a trap with matches at the basement door and hides with Josh in the house ventilation system. Brent cuts the door's lock off and opens the door, igniting the gas and triggering an explosion that knocks Kendall and Brent out and wakes Damon up.

Damon helps Carly and Josh evade their parents, but Kendall wakes up, stabs him in the cheek with a wire hanger, and pushes him over a stair railing, knocking him out again. The parents close in on the kids, but are interrupted by the doorbell; Brent's parents have arrived for dinner. When Brent opens the door, his mother pepper sprays him and his father stabs him... revealing that the unknown hysteria affects grandparents as well. Everyone chases each other through the house. Josh evades Brent, who attempts to hide from his father in his car in the garage. Kendall chases Carly outside and hits her in the head, but Brent's mother attacks her before she can finish Carly off.

Brent starts the car, drives it out of the garage, and crashes it, killing both his parents and knocking himself out again. Kendall prepares to finish Carly off, but Damon knocks her out with a shovel to the head.

Kendall and Brent wake up to find themselves restrained in the basement with Carly, Josh, and Damon watching them. They continue to exhibit symptoms of the hysteria, and the kids refuse to let them go. Kendall tearfully tells the children she loves them and asks to let them go. Brent continues, "But sometimes, we just want to--". The film ends before he can finish his sentence... leaving everything unanswered.