When Earth is devastated by a pathogen brought back by the first rover to return from Mars, Gwen finds herself one of very few survivors left on the planet. While trying to escape the violence and chaos that ensues after the disease has run its course, Gwen teams up with Pearl, a beautiful black horse she rescues from a local stable. Together she and Pearl travel to a remote cabin in the Oregon coastal forest belonging to Gwen’s deceased Aunt Elaine. Once there, Gwen makes a remarkable discovery left behind by her Aunt that allows her and Pearl to travel to places beyond her wildest dreams. What starts out as wild and crazy traveling adventures for Gwen and Pearl, soon becomes a conflict for Gwen as she struggles with being alone in amazing new environments with only her horse for company. Gwen finds herself missing the company of the survivors in a small community not far from her Aunt’s cabin. She especially finds herself missing the company of Calvin, a young man working as a medic in the community. Just when she feels the most conflicted with her strange new abilities, company arrives in the form of a younger girl and an alien boy. Eventually Calvin joins Gwen’s small troupe of travelers and what started as solo adventures for Gwen and Pearl soon becomes a journey with friends and a quest to save the human race.