From the New York Times bestselling author of All the Missing Girls and The Perfect Stranger comes a captivating thriller about two teens connected by family tragedies and a mysterious otherworldly radio frequency signal. Six months ago, Kennedy Jones suffered a horrible family tragedy, and since then she's lived with her uncle, sneaking out only occasionally to visit her childhood home. Nearby, Nolan Chandler is determined to find out what really happened to his brother, who disappeared without a trace two years earlier. Then Kennedy and Nolan find themselves drawn together by strange signs--for Kennedy, it's a disturbing pattern on her brother's radio telescope; for Nolan, it's a mysterious frequency coming from his brother's bedroom. When they realize their brothers also share dark pasts, they begin to wonder whether something is coming for them. Or are the signals a warning that something's already here?