Lealtad, amistad y capacidad de supervivencia son puestos en juego de forma definitiva para decidir el destino de la humanidad en la esperada conclusión de la trilogía del Mundo en ruinas. Cuando Kaelyn y sus amigos llegan a Toronto con la vacuna del virus que ha aniquilado a gran parte de la población, piensan que su viaje ha concluido. Sin embargo, la suerte los elude una vez más: un peligroso grupo de supervivientes los persiguen para robarles la cura cueste lo que cueste sin importarles lo que cueste. Obligados a volver a la carretera, Kaelyn redobla sus esfuerzos para encontrar un refugio seguro. Pero cuando el resto de su grupo empieza a desanimarse, las posibilidades de alcanzar el éxito comienzan a flaquear. Kaelyn está decidida a seguir adelante pero ¿estará dispuesta a entregar todo para seguir con vida? ENGLISH DESCRIPTION Kaelyn has proof her father's vaccine works--but the virus has stolen too much from her along the way. And the road ahead looks even longer. When Kaelyn and her friends reached Toronto with a vaccine for the virus that has ravaged the population, they thought their journey was over. They were wrong. Now they're being tracked by the Wardens, a band of survivors as lethal as the virus. The gang's leader intends to claim the vaccine for himself, no matter what the cost. Forced onto the road again, Kaelyn and her companions discover the Centers for Disease Control is still operating. The scientists there could reproduce the vaccine. But with the virus still spreading, the Wardens hot on their trail, and hundreds of miles to cross, Kaelyn finds herself compromising her morals to keep her group alive. Her conscience seems a small price to pay if protects them and their precious cargo. To survive this shattered world, will Kaelyn have to sacrifice all that's left of the girl she used to be?