Earthdark starts up immediately after the events of Crisis on Conshelf Ten, featuring the same first person narrator, Kepler Masterman, now edging very close to age 16. Kepler has now returned to his home on the Moon, ready to readjust back into his life and his relationship with his fiancée, Ann.
Things, however, are not that simple. The lack of gravity feels right, but everything else is frustrating and wrong. Kepler finds himself unhappy with the food, the blandness, the regulations—nearly everything, actually, constantly comparing his surroundings to better things on Earth, even after Ann sharply reminds him that in his six month stay on Earth, his intolerance of gravity meant that he didn’t see much of it.
This doesn’t help.
And even apart from culture shock, Kepler has a number of other issues to deal with: namely, spies, saboteurs, and the realization that he may not be able to trust his father.
[Also excitements with solar storms, which in the Moon environment can be deadly.]