Sienna Crenshaw knows the rules: 1) no time traveling beyond your natural lifetime, 2) no screwing with death, and 3) no changing the past. Ever. Sienna doesn’t love being stuck in the present, but she’s not the type to to break the rules. That is, she wasn’t the type until her best friend broke every one of those rules to keep Henry, her twin brother and Sienna’s ex-boyfriend, alive.
Suddenly, Sienna is caught in an unfamiliar reality. The upside? Henry is still alive. The downside? Sienna’s old life, including the people in it, has been erased. Now, Sienna and Henry must untangle the giant knot in time, or her parents and all the rest of the Travelers, will be lost forever. One problem: the only way to be successful is for Henry to die.