Paradise Orange: Immune 

Anne Burkes is the librarian in a small college town who finds herself leading a group of lucky survivors immune to an infection unleashed by vicious aliens who want to wipeout humanity, colonize the planet, and replace Earth’s verdure with their alien orange thicket. Anne and the others face an isolated existence without the help of technology that was also decimated by the aliens. They struggle to remain civil in the face of personal vengeance and of annihilation by their own military, while two seemingly benevolent alien scientists protect them from extermination by using them as an experiment.

Start the saga with the first book in the trilogy, Paradise Orange: Immune

It is available on Amazon.

https://www. Paradise Orange: Immune: 9798831575699: Stogryn, Stephen, Stogryn, Shelby: Books