[2][1] Western is haunted by his father's contributions to the development of the atomic bomb,[2] and tormented by his inability to save his sister Alicia—the protagonist of the novel's proto-sequel, Stella Maris—from suicide, which happens a decade before The Passenger takes place.

[3] Alicia was a mathematics prodigy who worked under the tutelage of Alexander Grothendieck (a real mathematician who shunned the field at the peak of his influence and chose to live in relative seclusion[4]).

The Western siblings grow up in east Tennessee as their father works at Oak Ridge on the Manhattan Project (with luminary physicist J. Robert Oppenheimer).

[6] The events of the novel are punctuated with short, italicized chapters about Alicia's treatment for schizophrenia due to hallucinations of a deformed figure the narrator named "Thalidomide Kid" who perpetually teases and belittles her and summons his ghostly cohorts to perform unwanted and garish entertainment acts.

Following a salvage dive to recover any survivors from a submerged airplane, Bobby discovers that the pilot's flight bag and data box are missing.

Now in hiding from the authorities on the advice of Kline (a private investigator), Western has his 1973 Maserati Bora seized and his bank account frozen by the I.R.S., ostensibly for failing to record in his taxes the money he inherited from his paternal grandmother.

John Jeremiah Sullivan writes in the New York Times that "The Passenger is far from McCarthy's finest work, but that's because he has had the nerve to push himself into new places, at the age of all-but-90.

"[5] Similarly, writing for Time magazine, Nicholas Mancusi notes that McCarthy's "first works of fiction to be published in 16 years begin in familiar territory but push his ambitions to the very boundaries of human understanding, where math and science are still just theory.

"[15] Nick Romeo also praised the novel in The Daily Beast, calling it "a powerful and thought-provoking distillation of many of the genres and ideas that have obsessed McCarthy throughout his career...The book's kaleidoscopic compression of sensibilities and subjects constitutes a new aesthetic in its own right.” [16] On the contrary, many have noted the lack of a coherent and perceptible plot, one that doesn't answer many of the opening questions set forth in the mysterious plane crash portion of the novel; Grady calls it "deliberately frustrating" and notes that "You can almost feel McCarthy swaggering a bit as, with great skill and elegance, he chooses time and time again to frustrate any desire the reader might have for either narrative or story.