An unexplained blackout renders all inhabitants of the English village Midwich unconscious for 24 hours, referred to as the "dayout". Upon awakening it soon becomes apparent that all child-bearing aged women are now pregnant. The women all give birth on the same day to healthy babies which grow and develop much faster than "normal" children. The Children bear a resemblance to their mothers, but are both male and female. The government, led by Major Westcott, pays a subsidy to the Children's parents and both educates and monitors them from "The Grange" facility in the village. Dr Zellaby, a villager who was away on the dayout so did not fall pregnant, becomes a primary carer on the staff and suspects that the Children are of alien origin. She shares her concerns with DCI Haynes, the local Police liaison for the village.
Several years pass, and the quickly-developing Children become aloof and with the exception of one child - Nathan - have an emotional detachment from the other villagers, including their parents. The Children develop telekinetic abilities, which they use to get their own way, forcing their parents to act against their wills, self-harming and killing themselves in two cases. Major Westcott reveals himself to be an adult Child, the sole survivor from a Russian village 30 years ago that had a dayout, but was bombed by Russian authorities out of fear of the developing Children. Under Westcott's guidance the Children subvert a nearby military base and use the soldiers to organise safe passage out of the village. The Children use their mental powers to force all the villagers to forget the Children exist, but Nathan warns his parents, Zellaby and Haynes who take cover underground and are unaffected by the amnesia wave. The Children remove Nathan from their group mind, leaving him in the village and allowing him and Cassie to run away. They then depart on a bus guarded by the military, and with Zellaby as a willing hostage to ensure safe passage. Unknown to all, Haynes had taken the place of one of the soldiers and overnight hidden an explosive device on the bus. He tries to persuade Zellaby to leave, but she refuses knowing that if she does so the Children will become suspicious. Reluctantly he detonates the bomb killing all those on board - Zellaby and the Children, but Westcott in a support vehicle survives, looking on in horror. Nathan and Cassie watch the explosion from the woods before walking away.
The series received mixed reviews. Lucy Mangan of The Guardian gave the first episode two out of five stars, feeling it did not make the most of its adaptational changes and topicality, with its emphasis on the perspective of female characters.[6] Nick Hilton of The Independent also gave it two out of five stars, deeming it 'humourless' and criticizing the production.[7] By contrast, Mark Kermode on Kermode and Mayo's Take praised the series' tone, use of horror and performances, saying it was a successful update of the novel.[8] Carol Midgley of The Times also gave it four stars, praising the atmospheric direction and Farr's scripts.[9] On review aggregatorRotten Tomatoes, the series holds an approval rating of 71% based on 14 reviews. The website's critics consensus reads: "This adaptation of John Wyndham's classic novel is often cuckoo in an off-putting way and overstays its welcome with a bloated runtime, but it holds some diabolical delights for viewers who enjoy a science-fiction nightmare."[10]