What happens to the twin left behind?

Scottie O'Doul isn't looking forward to starting her senior year. Last May, her identical twin sister, Cait, died in a car crash involving the school's beloved football coach. There's been no official report on the accident yet, but before she died, Cait told Scottie a disturbing secret. When Scottie reveals this secret, half the town turns against her, certain that Scottie is lying to protect her sister and that Cait deliberately lost control of the car.

Scottie knows her twin would never take her own life, or someone else's, but how can she prove it? As she faces bullying and hostility at school, she starts to wonder if what Cait said was even true. Turning to running to break through her grief, Scottie finds a new world and a new sense of self outside her twinness. She also reconnects with her old boyfriend, who had a terrible accident of his own the same day Cait died. Could there be a connection?

As she runs mile after mile, Scottie keeps trying to fit the jigsaw pieces together and find the true picture of what happened to Cait and what was really going on at school before the crash.