第五名乘客剧情为：Suburban America gone haywire. In the midst of a serial abductor/killer's rampage, a beautiful young teen, Riley Lawson, goes missing. When her desperate parents, Will and Kate, are contacted by her kidnapper, an insufferable FBI Special Agent takes charge of the case.But, from deep within the psychopathic subterranean world created by Otis, Riley turns the tables on her tormentor, manages to escape and to contact her parents. And, fed up with the tragi-comic inability of the FBI to find their girl, Will, Kate, and Riley's brother, Reed decide to take matters - and justice - into their own hands. But when Otis's brother, Elmo, shows up unexpectedly, the Lawsons find themselves mired in unusual and macabre consequences of vigilantism.