The Rorgons are sentient robots. They hate organics.

They seed the entire planet with a cruel pathogen which turns the victims into a plant that craves blood. It is not a hundred percent effective but the great thing about it is those unaffected are hunted by those affected.

John and Jane meet and steal a Ferrari. They find a fort with soldiers and other survivors.

They go out a number of times to collect food and have some close scrapes with the zombies. Doctor Jones invents a cure and they trial it. The Ventura arrives and disperses the cure successfully. Unfortunately the Rorgons return and decide to re-apply the pathogen. The Ventura stops them. John and Jane marry and make a home for their surviving children.