For the first time Morrey, Serge and Tony make a space expedition without Chris, who has become Deputy Director of U.N.E.X.A.. Their dedtination is Pluto, which since its discovery in 1930 has always been thought the most distant of the planets. Now, however, the powerful instruments of the Lunar Observatory have detected a change in its orbit which suggests the existence of another planet beyond it. The task of Morrey and his crew is to learn more about this mysterious Planet X and also to try out a new form of propulsion which will send their ship through space faster than ever before.The launching is a complete success, but as the crew are approaching Pluto they make a terrible discovery about their ship...
I first read this in 1981 when I was given it as a school prize for success in examinations. Re-reading it recently has made me relish its simple boys own adventurism..
Rule number one of space exploration in the Walters-verse: always have a spare ship on hand for a rescue. Rule number two: have Chris Godfrey available to pilot it.
Pluto is acting weird, so the other three boys go out to investigate. We can now travel to 12 million MPH, folks! Which is good, because when things go pear-shaped, there's just enough time for Chris to work his heroics.
Although the real hero is Tony Hale, as it turns out (I won't spoil that part).
This entire review has been hidden because of spoilers.