Sullivan has agreed to help Jan Rodricks with his plan to sneak aboard an Overlord ship. Jan writes a letter to his sister, explaining that due to time dilation at the speed of light, the trip will only seem to take a few months to him, but to her it will seem like many years, and she will probably be long dead when he returns. His plan is to hide himself away inside the sperm whale model that Sullivan is preparing for the Overlords. Inside a little capsule in the whale, Jan will inject himself with a drug that will put him to sleep for six weeks--most of the trip to the Overlords' homeworld. At that point, he will give himself up and, hopefully, get a chance to see the Overlords' planet before he is shipped back to Earth, returning eighty years after he left it.
Sullivan shows Jan the metal skeletal framework of the sperm whale. Rather than actually capturing and stuffing a sperm whale and a giant squid, the scientists use advanced techniques to create fake but entirely realistic models. A few weeks later, Sullivan stands on Easter Island next to his impressive achievement. He is awaiting the arrival of Karellen to inspect the model, showing a sperm whale and a giant squid locked in combat. Karellen is impressed, but both Sullivan and Jan, who watches from a few hundred yards away, wonder whether Karellen has guessed the secret inside the whale. Karellen makes a comment about the story of Jonah and the Whale, but he does not seem to have guessed the whale's secret. Finally, the time comes for Jan to enter the whale. He climbs in and is locked away inside. Jan checks the systems inside the whale pod, then injects himself with the sleeping drug. He is asleep long before the Overlords' ship goes to light speed.
Karellen holds a press conference. He first reveals that a human stowaway has made it onto an Overlord supply ship. He provides Jan Rodricks' name, but he will not say how Jan snuck onto the ship. He then moves on to the more important matter of the meeting. Karellen notes that many people have become restless to get into space and are wondering why the Overlords will not allow them to. Karellen assures them it is more for their own good than anything else. He gives the analogy, "what if a Stone Age human found himself in a modern city?" and shows them a holographic projection of their galaxy. With billions of stars and worlds to consider, Karellen says, humanity could not hope to be able to handle them. Karellen says that one of his duties has been to "protect" humans from the "forces that lie among the stars." Someday, humans may colonize all the planets in their solar system, but beyond that they can never go: "the stars are not for man." After this conference, Karellen broods in his ship. He knows that the "golden age" of the Earth is coming to an end and that a future of which humans could not even imagine is approaching.
It is difficult to analyze a novel like Childhood's End without admitting its flaws. The narration of the novel works on two levels: first, there is the very broad view, where the perspective is pulled back very far. In this perspective, the narrator describes the great changes that occur on Earth, such as the development of a utopia or the growing restlessness and boredom of mankind. But author Arthur C. Clarke then zooms in to a much tighter perspective in an attempt to illustrate these changes. More often than not, this shift causes problems. Clarke is not a "great novelist" in terms of his style and craft. His ideas are often interesting and his philosophical explorations can be very original, but his writing is often, for lack of a better word, bad. For instance, there is no real relationship between Jan Rodricks finding out where the Overlords' homeworld is and his decision to sneak on to the Overlords' ship. He could have decided to sneak on the ship without ever having attended Rupert Boyce's party. In the scenes where Jan and Dr. Sullivan prepare to sneak Jan into the whale, the narrator tries to playfully cover up the plan rather than simply spelling it out. This would be more effective if the plan wasn't obvious from the minute that Rupert Boyce mentioned that Sullivan was stuffing a sperm whale for transport to the Overlord home world.
Then there is the long letter by Jan to his sister Maia. The purpose of this letter is to explain the nature of the theory of relativity, so the reader can understand why eighty years will pass for Maia while only a few months will pass Jan on the light speed ship. The purpose of this letter is obviously to instruct the reader much more than Maia, and this makes it rather unrealistic; in such an age of utopian enlightenment, it's almost unthinkable that Maia would be unaware of the theory of relativity (indeed, any serious science fiction reader since the 1950s would be well aware of the theory or its effects). The letter is stiff and unrealistic, devoid of any real emotion, and only serves to show just how flat Clarke's characters are. There is a sense that Jan's trip is little more than a plot device, so the reader can see what the Overlords are really like, and perhaps find out what they're doing.
This sense is supported by the fact that Karellen uses it as an excuse to tell humanity that they will never conquer the stars. The reasons he gives—that humanity simply couldn't handle the "forces" of outer space and that humans' little minds simply couldn't comprehend the vastness of it—these reasons are very unconvincing, both to the characters and to the reader. Karellen's comments directly contrast something said earlier in the novel by Stormgren: "...taken one at a time, I don't think [Karellen]'s mental gifts are quite outside the range of human achievement." The reader may reasonably agree with Stormgren's assessment. Karellen's reasons seem to be a poor excuse at best; the Overlords may have been necessary to prevent humanity from destroying itself in a nuclear holocaust, but now they that they have refined human sensibilities, they are only holding humanity back. There turns out to be a reason for the Overlords' behavior, but as Childhood's End progresses, its flaws, both in terms of style and premise, become more and more pronounced.