A Los Angeles District Attorney (Hackman) is attempting to take an unwilling murder witness (Acher) back to the United States to testify against a top-level mob boss. Frantically attempting to escape two deadly hitmen sent to silence her, they board a Vancouver-bound train only to find the killers are onboard with them. For the next 20 hours, as the train hurls through the beautiful but solated Canadian wilderness, a deadly game of cat and mouse ensues in which their ability to tell friend from foe is a matter of life and death...