On a warm Fourth of July in the quiet New York town of Byram Hills, Nick Quinn watches as his wife and daughter die—along with his closest friends and family—in an unprecedented terrorist attack.

Amid the disaster, Nick is approached by one of his closest friends, gunshot and dying. With his last breath, he hands Nick an antique pocket watch that possesses the power to rewrite the recent past.

Emotionally shattered and desperate, Nick uses the watch and is shocked to find himself propelled back in time to where he was an hour ago, before the attack on his town.

At the top of each hour, the watch sends him back two hours to live one hour again, a backwards march to relive each hour of his day. A twelve-hour journey providing precious but limited time to protect Julia and Katy and uncover the source of the threat.

But each time Nick thinks he's solved the crime and secured the future, he uncovers new levels of deception and betrayal, ultimately...