The Oasis

From publisher blurb:

In the Red Hills people tell a lot of stories, the talk of a pleasant valley where everything is green and growing, where people have enough water and nobody fights. They all tell stories of a great fiery star crashing to earth during the fall. Some of these stories are true and the people of the Greenvale do seem to have everything they need but lately some of them are learning the secret of the valley and others are, well others are just plain disappearing. These folks might need more help than they realize.