Nessa Calder has died seventeen times. Seventeen times, she has watched the same seven days unravel. Seventeen times, she has tried to survive the catastrophe waiting at the end of them. And seventeen times, she has woken at 6:17 a.m., carrying every memory of how she failed. By the eighteenth loop, she knows the rules. Or she thought she did. People are beginning to remember things that never happened. The dead are returning with secrets they couldn’t possibly know. And after every reset, someone Nessa trusts becomes a little less familiar. The Identity Verification System calls them Contradictions. Its instructions are simple: identify them, complete the missions, and prepare for the coming disaster known as the Stillwake. But the system has started issuing impossible assignments. Its latest target is Nessa herself. With seven days left, Nessa must uncover who—or what—is changing the people around her before she loses the few people she has left. Yet every answer creates another problem, and every death brings her closer to a truth that someone has killed her seventeen times to keep buried. She used to believe death was the worst thing that could happen to her. Now she’s beginning to suspect that something worse happens when she survives. Because the dead can lie about how they died. The living can lie about who they are. And somebody in this loop remembers what Nessa did first.

Maya Bennett spent her entire life putting her family first. She paid their bills, sacrificed her dreams, and loved them even when they gave her every reason to stop. She believed that when the world finally fell apart, the people she had spent years protecting would protect her in return. She was wrong. When Blackfall destroys civilization, Maya discovers that survival has already become a privilege reserved for the people her family considers worth saving. Her mother, Evelyn, chooses her son. Her brother, Daniel, turns away from her. And Adrian, the boyfriend she trusted with her life, watches as the shelter doors close between them. Left outside to face the horrors of the apocalypse alone, Maya dies realizing that the people she would have died for never intended to save her. Then she wakes up thirty days before Blackfall. Back on September 3, with every memory of her first life intact, Maya is given something she never thought she would have again: a second chance. This time, she will not spend her money keeping her family comfortable, beg for affection from people who despise her, or mistake being useful for being loved. She knows what is coming, and she intends to be ready. But preparing for the end of the world is only the beginning. A trail of suspicious payments leads Maya to Northbridge Emergency Logistics, a restricted storage unit numbered 997, and a mysterious evacuation passenger list that raises a terrifying question: how much did her family know about Blackfall before the rest of the world? With the help of Ronan Hale, a former Northbridge employee with secrets of his own, Maya begins uncovering a network of preparations that suggests her first death may not have been as simple as betrayal. Meanwhile, the people who abandoned her begin noticing her sudden independence, and someone is willing to go to dangerous lengths to keep her from discovering the truth. As Blackfall approaches, Maya must decide how much she is willing to risk for answers. Every day brings her closer to the disaster she remembers, but this time, she refuses to walk blindly into the same fate. The world may end in thirty days. Her family may have already chosen who deserves to survive. But Maya Bennett has made her own choice. This time, she won't die for them.

The first time Syraeth Nyvelle died, Vaelith Orzayne watched the world take her from him. The second time, he would learn why it had chosen her. The world did not end all at once. It ended in pieces—one city swallowed by infection, one hospital abandoned, one familiar voice disappearing into the dark. Vaelith survived long enough to learn that there were worse things than dying. Watching Syraeth become one of them was the worst. She was the one person he had never imagined a world without. So when an experimental treatment fails and her heart stops beneath his hands, Vaelith refuses to accept that this is how their story ends. He tries everything he has left to bring her back. Then the impossible happens. A portal tears open above her body, revealing three circles suspended in a darkness scattered with stars. One holds a world that no longer exists. Another shows the nightmare unfolding around him. The last contains a future so devastating that he cannot bear to look at it for long. But it is the past that breaks him. In a memory from his childhood, Vaelith sees a little girl standing beside him. He knows the photograph. He remembers the day. He remembers being alone. The girl has Syraeth's face. He did not meet her until eleven years later. When Vaelith gets another chance at the life he thought he had lost, he returns with one purpose: find Syraeth before the world takes her from him again. Yet the closer he comes to uncovering the truth, the more his memories begin to betray him. The infection is changing. The future refuses to stay where he left it. And Syraeth, alive and standing before him, may know more about their impossible history than she is willing to admit. Vaelith thought time had given him a second chance to save the woman he loved. He never considered that their first meeting might have been a lie. Because some people enter your life once. Others find their way back to you, no matter how many times the world ends.