After Earth becomes no longer habitable, the human race is forced to leave their planet and build a new life on Mars. After years of adjusting to the new planet, they are able rebuild homes and living environments to perfection and this time, the human race is determined not to let their planet go to hell. However, every few years or so, a small group is selected through a series of tests to be part of a small team to fly back to Earth, for supplies, certain resources and anything they can salvage. It is a dangerous journey and most do not return. Amy, an 18 year old girl is one among eight others to be sent to Earth, but when their ship crashes, they are surprised to find dangers they could never have expected. They have lost all contact to home, they are trapped, and they are not alone.
Season 4 of The Virus Within
Trinity is familiar with zombies, being one herself, but when strange zombies start appearing, she realizes that the world she knew might be changing yet again.
When a dangerous set of scientific notes are discovered, Trinity and her friends don't realize anything is wrong until a frantic radio call comes in. Unaware of the notes, they race to the south and struggle to determine where the strange zombies came from. The zombies are unlike any ranks previously seen, and they aren't as predictable. Some have new tricks hidden up sleeves, forcing any Stronghold they encounter to quickly adapt to the new challenge or risk being overrun. Secrets never remain hidden, and zombie apocalypses never make life easy.