Jack (Jeff Bridges) is a top-rated radio shock-jock in New York City. He lives the high-life of celebrity until one night when his words incite an irate caller to go on a murderous spree at a nightclub. Amongst the victims, the wife of a medieval literature professor (Robin Williams). Three years pass and Jack has had a complete reversal of fortune. Fired from his radio gig and now reduced to running a video store with his erstwhile girlfriend (Mercedes Ruehl), Jack seeks an explanation for the cruel twists of fate that life has given him. Deciding to commit suicide, Jack is saved by the professor, now a deluded, unstable homeless man calling himself Parry who after the murder of his wife three years before, believes he is on a quest for redemption by finding the Holy Grail. Both broken men in their own ways, Parry takes Jack on the quest through Manhattan, as Jack begins his own quest to change his fortunes by helping Parry regain his sanity and put his life back together.