Critics agree the film doesn't capture the spirit of Jack Kerouac's Beat novel.By Fallon Prinzivalli Kristen Stewart in "On The Road" Photo: MK2 Productions Kristen Stewart hit the 2012 Cannes Film Festival to debut her latest film, "On the Road." Adapted from Jack Kerouac's Beat Generation novel, the film centers on writers Dean Moriarty (Garrett Hedlund) and Sal Paradise (Sam Riley) as they journey across America with Dean's wife, Marylou (Stewart), living in a whirlwind of sex, drugs and writing. Despite the American classic being considered unadaptable, director Walter Salles took on the ambitious project, much to the dismay of critics.