In the fourth and final installment, everything is on the line. Merrick's life is in the balance and Lily is their only hope. Ellie and her new powers are miraculous, but also problematic; if she's with the bunker family, they won't be able to sense when the Lighters are there. There are many new members to the bunker and sparks will fly, and with the food shortage, they will all have plenty to deal with. Miguel is intrigued with Rylee, her past and her spunk. Ryan and Elli are barely scratching the surface of their relationship. Cain and Lillian will have to deal with Daniel, who has no qualms about showing his true feelings for her. And Sherry and Merrick...what will happen to this happenstance family who have worked so hard to come together? Can they all survive? Can they all withstand the new enemy that is right outside their door? Can they beat the Lighters, once and for all...