In 1978, Mary Mattock has her first period, and due to menstrual psychosis, murders her parents with a hatchet. Deemed mentally unfit, Mary is placed in Kings Park Psychiatric Center, where she is raped and impregnated by a guard in 1989. This incident is covered up, and after being told her child was a stillbirth, Mary goes on a rampage through the hospital. The police find Mary wandering the grounds, and open fire on her after she throws the severed head of her rapist at them, ending her killing spree. "Mary Hatchet" subsequently becomes a folklore figure, with local youngsters celebrating the Mischief Night-esque "Blood Night" in her name.
Following the events of Are We There Yet?, Nick Persons (Ice Cube) has married Suzanne (Nia Long) and moved her, Kevin (Philip Daniel Bolden), and Lindsey (Aleisha Allen) into his apartment, also purchasing a 2007 Cadillac Escalade (after the destruction of his Lincoln Navigator SUV). He has also sold his sports memorabilia store to his best friend, Marty (played by Jay Mohr in the first film). While getting ready for an interview with Magic Johnson, Suzanne tells Nick that she is pregnant and they later find out that there will be twins.
The last human colony struggles to survive underground, beneath a land of nightmarish mutants who seek to destroy them. But when the mutant breaks inside humanity's final stronghold, the battle for survival pits the human colonists against their deadly invaders miles below the Earth's surface.
The film centers around Angela Marks, an ambitious, image-conscious businesswoman working for over-demanding boss Mary. When Angela becomes unexpectedly pregnant at the peak of her career, her life with her divorce attorney husband, Curtis, is turned upside-down. The film begins with an inconvenient pregnancy that leads to a nine-month roller coaster ride as Angela and Curtis try to cope — even as the interference of best friends Danny and Sylvia escalate the situation into a battle of the sexes.
The story begins with the Howards, a young, married couple living in New York. Craig (James Purefoy), an unpublished writer, and Samantha (Heather Graham), a school teacher, are desperate to have a baby. Their hopes are dashed when Samantha is diagnosed as infertile and the couple can't afford the medical treatments that might allow her to conceive. Just when it seems their dreams are impossible, the couple are given the opportunity to receive free treatments from a new, and relatively unheard of, fertility clinic. The Spiritus Research Clinic is in Lakeview, a small town two hours away, and they move to the clinic.
A young couple, Zach and Samantha McCall, have recently married and have gone to the Dominican Republic for their honeymoon. They visit a fortune teller who keeps repeating to Samantha, "they've been waiting". Afterwards, the couple finds themselves lost on an unknown street they do not remember seeing. Wanting to return to their hotel, they get offered a lift from a pushy cab driver who offers to take them to a local bar. The couple reluctantly accepts. The couple begin partying and both soon pass out drunk. They are both then seemingly taken to an underground chamber in the nightclub where Sam is subject to some kind of ritual by an unseen force. The next morning, Zach and Sam wake in their hotel with no memory of the previous night.
On a desolate planet, a team of 12 Xeno project scientists are conducting an archaeological excavation of the ruins of an ancient civilisation. Shortly after an underground tomb network is found to contain crystals and wall inscriptions, photographer Dean White (Dominic Jephcott) is engulfed in a rock blast and left incapacitated. Deciphering the alien language in the caves, xenolinguist Mitch (Trevor Thomas) theorises that the civilisation was built on the concept of dualism: the planet orbits a binary star, and a pair of twins seems to have ruled the race that once inhabited it. Medical assistant Sharon (Heather Wright) discovers that an energy field surrounds the crystals, which causes her to deduce that a "chemical intelligence" controlled life on the planet.
King Kong, after being shot down from the World Trade Center, is kept alive in a coma for about 10 years at the Atlanta Institute, under the care of surgeon Dr. Amy Franklin (Linda Hamilton). In order to save Kong's life, Dr. Franklin must perform a heart transplant and give Kong a computer-monitored artificial heart. However, he lost so much blood that a transfusion is badly needed, and to complicate matters, Franklin says there no species of ape or other animal whose blood type matches Kong's. Enter adventurer Hank "Mitch" Mitchell (Brian Kerwin), who captures a giant female gorilla, who is dubbed "Lady Kong"; in Borneo (Mitchell theorizes that Borneo and the island from the first movie were once part of the same landmass), bringing her to the Institute so her blood can be used for Kong's operation. The transfusion and the heart transplant are a success, but Kong escapes along with the female.
During a sing-along at Camp Hiawatha in 1981, two revelers sneak away to have sex, and are killed by an unseen assailant. Twenty-four years later, four friends (Angela, Jen, Mario, and Vade) are driving through the area on their way to Boston. The quartet becomes lost (passing the same sign several times) and their SUV breaks down after night comes unusually early. All the electronics fail to work, and the group is thrown into hysterics when screams emanate from the surrounding forest, and the vehicle is pelted with debris, prompting them to spend the night in it.
Lucy, Kit, and Mimi are three friends who live in a small Georgia town. While children, they bury a "wish box" in the ground, and vow to dig it up on the night of their high school graduation, also pledging to stay best friends forever; however, as they grow up, their friendship fades due to their different approaches of high school. Lucy becomes the valedictorian, Kit becomes the most popular girl in school, and Mimi faces teenage pregnancy. On the night of their graduation, they keep their promise and get together to open the "wish box". As they start talking again, they remember their old wishes while burying the box: Mimi wanted to travel to California, Lucy wanted to see her mother again, and Kit wanted to get married. Mimi brings up the topic of going to Los Angeles for a record contract audition. They all leave together: Lucy to visit her mom in Tucson, Arizona, and Kit to visit her fiance in Los Angeles.
Unable to bring in anymore money for Leroy, her abusive pimp, the pregnant Rose tries to run away in the middle of the night, but is caught by Leroy. Using a clothes hanger, Leroy performs an impromptu abortion on Rose, unintentionally killing her in the process. Leroy disposes of Rose's baby in a dumpster, where its cries attract the attention of a homeless man, who raises the disfigured child as "Hanger".
Several hundred years into the future, mankind has been relegated to the position of a minority species being replaced by a clone-race called "Homo technis" or "Konstrukts" which is itself being supplanted by the genetically engineered race "Homo superior". The Homo superior have enhanced themselves with DNA from a race of hostile extraterrestrials called Nephilim who are known for their superior military skills, to wipe out all the Homo sapiens and Homo technis "lesser" races from the galaxy. In order to save the "lower" races, Homo technis develops a genus of sapiens called "breeders", with an ability to bring multiple births to term quickly.
The events take place 20 years after a nuclear war which was followed by plagues. No children have been born in 15 years, and people want to gain control of the first pregnant woman - Sara. Running out of water, Sara and her mother are forced to leave their shelter in Samuel's basement and join other groups of refugees who call themselves internally displaced people. Michael is a disc jockey who operates a radio station at one of the camps. David runs a gang of looters.