Children of Men is set on the year 2027, a time when humanity has been experiencing global infertility for the last 18 years. Because of this, humanity stands at the brink of extinction. United Kingdom is constantly flogged by asylum seekers trying to escape the chaos and war from other parts of the world. It serves as a military state deploying British government forces to control the immigrants. A bureaucrat named Theo Faron is kidnapped by a militant immigrant’s group called the Fishes. The Fishes are led by Theo’s former wife, Julian Taylor.
Julian offers money to Theo in exchange for transit papers for a young refugee named Kee. The transit papers that Theo obtains requires a companion for the bearer so Theo agrees to accompany Kee after being paid by another large amount of money. A Fishes member, Luke drives them to the coast along with a former midwife named Miriam. Midway, they are ambushed by armed men and Julian becomes one of the casualties. The remaining people in the group heads to a safe house.
In the safe house, Kee confesses that she is pregnant and Julian’s plan involves handing Kee to the “Human Project” with Theo’s help. The “Human Project” is a group that is supposed to specialize in treating infertility. Luke on the other hand, dissuades Kee from going with Luke. Theo finds out that Luke was the one responsible for the ambush and his goals include taking over as leader of the Fishes and using Kee’s baby for the revolution. Because of this, Theo escapes with Kee and Miriam in tow. The three end up in Jasper Palmer’s place, a very old friend of Theo.
The group plans to reach Human Project by boarding the ship Tomorrow. Palmer suggests asking for the help of a comrade of his, Syd, in smuggling them inside the ship when it arrives offshore from the Bexhill refugee camp. The Fishes traces Palmer’s place and they are ambushed again. The group escapes as Palmer tries to stall the members of Fishes. On their way to Bexhill, Kee begins experiencing contractions. Miriam acts like a maniac to distract the guards and she’s taken away.
When they reach the camp, Theo and Kee meet Marichka who help Kee when she gives birth to a baby girl. The day after, with the outbreak of war between the British government and the refugees, Syd tries to capture Theo and Kee when he learns about the bounty on their heads but Theo and Marichka manage to fight him off. On the other hand, Kee and the baby fall into the hands of the Fishes. Theo searches for them and finds them in an apartment surrounded by the military. Amidst the rain of bullets, Theo rescues Kee and her baby and they are led Marichka to a boat anchored in a sewer. They board the boat and Theo rows Kee and the baby to safety. The movie ends with Theo dying from the shot wounds he acquired when he saved Kee and her daughter.