It is June 21st, the longest day of the year, and new mother Camilla’s life is about to change forever. After months of maternity leave, she will drop her infant daughter off at daycare for the first time and return to her job as a literary agent. Finally. But, when she wakes, her husband Luke isn’t there, and in his place is a cryptic note. Then it starts. Breaking news: there's a hostage situation developing in London. The police arrive, and tell her Luke is involved. But he isn't a hostage. Her husband --- doting father, eternal optimist --- is the gunman. What she does next is crucial. Because only she knows what the note he left behind that morning says.

Twenty-two-year-old Olivia has been missing for one day…and counting. She was last seen on CCTV, entering a dead-end alley. And not coming back out again. Julia, the detective heading up the search for Olivia, thinks she knows what to expect. A desperate family, a ticking clock, and long hours away from her husband and daughter. But she has no idea just how close to home this case is going to get. Because the criminal at the heart of the disappearance has something she never expected. His weapon isn’t a gun, or a knife: it’s a secret. Her worst one. And her family's safety depends on one thing: Julia must NOT find out what happened to Olivia --- and must frame somebody else for her murder.

Late October. After midnight. You’re waiting up for your 17-year-old son. He’s late. As you watch from the window, he emerges, and you realize he isn’t alone: he’s walking toward a man, and he’s armed. You can’t believe it when you see him do it: your funny, happy teenage son kills a stranger, right there on the street outside your house. You don’t know who. You don’t know why. You only know your son is now in custody. His future shattered. That night you fall asleep in despair. All is lost. Until you wake...and it is yesterday. And then you wake again...and it is the day before yesterday. Every morning you wake up a day earlier, another day before the murder. With another chance to stop it. Somewhere in the past lies an answer. The trigger for this crime --- and you don’t have a choice but to find it.

When Martha finds herself struggling to balance early motherhood and her growing business, her sister Becky steps in to babysit her niece, Layla, without a second thought, bringing the two women closer than ever. But then the unthinkable happens, and Becky is charged with murder. Nine months later, Becky is on trial and maintains her innocence --- and so does Martha. Unable to shake the feeling that her sister couldn't possibly be guilty, Martha sets out to uncover exactly what happened that night, and how things could have gone so wrong. As the trial progresses, fault lines between the sisters begin to show --- revealing cracks deep in their relationship and threatening the family each has worked so hard to build.