American investment banker Ben Hartman arrives in Zurich for a ski holiday, the first time he's been back to Switzerland since his twin brother died there in a tragic accident four years earlier. But his arrival in Zurich triggers something far more sinister than his brother's fate. When Ben chances upon Jimmy Cavanaugh, an old college friend, Cavanaugh promptly pulls out a gun and tries to kill him. In a matter of minutes, several innocent bystanders are dead - as well as Cavanaugh - and Ben has barely managed to survive. Plunged into an unspeakable nightmare, Hartman suddenly finds himself on the run.