Slowly, Jeffrey's dreams, in which he walks on alien worlds, begin to break into his waking world. He stops going to school, and the life of routine that George and Jean had been enjoying comes to an end. Jennifer, since she is younger, advances even faster than Jeff; she can control objects and even draw nourishment by transplanting food from the refrigerator to her stomach. Soon, children all over the world are displaying these strange abilities. No children are spared: "humanity had lost its future, for the heart of any race is destroyed...when its children are taken from it." Finally, Karellen speaks to the world once more.
Karellen reveals the truth: the Overlords were sent by a higher power, which they call the Overmind, to act as "midwives" to the birth of the next stage of human existence. The Overlords were sent because mankind had started to scientifically examine phenomena such as telepathy and extra-sensory perception. If they succeeded in discovering these secrets, Karellen says, they would have become "a telepathic cancer" that would have spread throughout the universe.
But more significantly, Karellen tells the people of Earth that the minds of the Overlords themselves have reached the end of their development. The same is true of humans in their present form, but humans are capable of making the leap to the "next stage." This stage is to join the Overmind, the entity that the Overlords serve. The Overlords believe the Overmind is trying to grow and "increase its awareness in the universe." The change will be swift, in a few years, and destructive. Karellen tells the adults of Earth that "all the hopes and dreams of your race are ended now." The Overlords will soon round up all the children and take them to a protected part of Earth. Karellen can only give the remaining humans only one consolation: that long after the Overlords are forgotten, a part of the human race will still exist—and for that, the Overlords envy humans.
Jeffrey and Jennifer are taken away from the Greggsons. The same happens with children all over the world. The adults who are left either spend their last remaining days traveling the world, or they commit suicide. The people of New Athens decide to annihilate their island with a nuclear explosion, and George and Jean are there when it explodes, in each other's arms.
The truth is revealed: the children of Earth are no longer the children of humanity. They are destined to move beyond their bodies and lose their individuality in the entity called the Overmind. Here, the line between science and myth begins to blur. Author Arthur C. Clarke has confronted the reader with a creature so omnipotent, so amorphous, and so transcendental, that it is basically a form of God. The Overlords' similarity to Satan and his rebel angels becomes even more obvious here, where they are forever denied the divine presence of joining the Overmind. Though they feverishly work to understand the Overmind better, they have no choice but to serve its needs. These chapters are unquestionably depressing. Karellen's reassurances that humanity has given birth to "something wonderful" seem like cold comfort for the eradication of mankind as it once was. The nuclear death of George and Jean is tragic, if somewhat melodramatic.
These chapters also reveal the mythic framework upon which Clarke has hung a science fiction premise. In a way, Childhood's End is nothing less than a depiction of Armageddon. The Devil, or the Antichrist, arrives in the form of the Overlords. The Overlords actually end strife and conflict, rather than bringing it, but they also herald the end of humanity. The screeching of their ships in the atmosphere is the metaphoric call of the trumpet to Judgment Day. But the only people worthy of joining God, or the Overmind, are the children. Clarke has created a science fiction version of Armageddon, with both God and Satan as aliens, and the humans that join "God" are part of an evolutionary development away from Homo sapiens.