In the story, Clyde Langer and Rani Chandra, two alien investigators, try to figure out why they seem to be the only people left on Earth.
To give Gavin a normal life he gave him a ring called a bio-damper to wear.
As a result nearly all of the humans on Earth, along with moving vehicles, are removed and suspended so that two royal robots can find Gavin and return him to his planet.
Gavin is sceptical, but before they can persuade him to help, a strange noise is heard and he slips away whilst Clyde and Rani try to work out what it was.
Clyde and Rani find Gavin at the nature reserve he wrote about in his diary and have him remove the bio-damper which hides him from the robots.