In the near future, earth's atmosphere has degraded. It's no longer safe to be outside without an oxygen device. Plant and animal life has ceased to exist. Following the disappearance of Darius, his wife Maya and daughter Zora are surviving alone in their bunker. Everything changes when strangers arrive, the first they've seen in years, seeking help. They claim to come from Philadelphia, and need to speak with Darius, so he can fix their oxygen device before it fails. After the strangers show their dubious colors, Zora finds herself tied up inside the bunker with no way to let anyone in. Tess and Maya are forced to journey to Darius' dead body to get his bunker keycard. Upon their return, the action escalates with Lucas killing Tess for her deception, and Maya and Zora escape before Lucas destroys the bunker. They journey to the shelter in Philadelphia, and are able to help fix their machine to build hope for a better future.