The story is set in post World War II America. The country is booming, an affluent society emerges and with it a restless youth. Kerouac coined the term "the Beat Generation" to describe this new group of people.
In this vein, we follow Sal and Dean as they travel across the country searching for experience and some unattainable meaning.
As mentioned above, the main characters are Sal Paradise (Sam Riley) and Dean Moriarty (Garrett Hedlund). The pair meet in New York, where Dean's energy and enthusiasm spurs Sal -- a writer struggling with a lack of inspiration -- to take to the road.
Their journey on the road is flavoured with sex, drugs, literature and music, and how these stimulants effect and alter relationships, primarily between Sal and Dean, but also between Dean and his numerous love interests.
The pair form a close bond. Strains are, however, placed upon their friendship, especially over Dean's philandering which creates an ever-present sense of pathos.
Their endless wandering, furthermore, is symbolic of the loneliness they each feel. It seems they are always trying to fill some emptiness, which they never quite can.
The punchy prose and the wealth of imagery made the book such a success, likewise in the film there were beautiful panoramic shots of the open road and of course the dialogue had a lot of material to draw on, nonetheless, there was a staleness to the film.
Strangely, Sal was played by an English actor, whose accent was awful. The film makes the Beat Generation seem infantile, which is not felt in the book.
To compare any movie to its book counterpart is a mistake, but in this instance it would be detrimental. As a stand alone movie, On The Road is mediocre at best.