Robert De Niro and Paul Dano play a father and son who reunite after 18 years of estrangement in "Being Flynn," and they approach their roles in such polar opposite ways, it's as if the actors themselves have been estranged, as well.

De Niro, as the alcoholic, ex-con, would-be novelist Jonathan Flynn, is all delusional bombast; he insists everything he writes is a masterpiece, and his bravado barely masks his insanity. Dano, as Flynn's aimless, hipster son, Nick, may actually have some talent and insight as a poet but he's meandering between jobs, homes and girlfriends.

They're forced to get to know each other when Jonathan, suddenly finding himself fired from his job as a cab driver and homeless, turns up at the shelter where Nick works (because Nick has nothing better to do, not because he has some great, altruistic urge to improve humanity). This might sound like a massive plot contrivance, except it actually happened, as detailed in Nick Flynn's bestselling memoir "Another (Expletive) Night in Suck City." Of course, that title wouldn't have flown at theatres, but "Being Flynn" is an unfortunately forgettable substitute.

De Niro's taking big bites out of one of the meatier and more serious roles he's had in a while; Dano, meanwhile, is dialed down and constantly reacts with deadpan incredulity. Individually, they achieve some compelling moments. But rather than providing an intriguing contrast, these disparate performances undermine the cohesion and flow of writer-director Paul Weitz's film.

The famously committed De Niro may actually be too convincingly obnoxious here, and a lot of that has to do with the singularity with which the character is written on the page. His character is a bloviating, condescending, hateful racist, and then all of a sudden at the end we're expected to embrace him. Dano at least gets to experience more of an evolution, as Nick delves into substance abuse and recovery and falls into and out of a relationship with one of his co-workers, played by Olivia Thirlby.

The other woman in Nick's life -- his hardworking but self-destructive mother, played by an underused Julianne Moore -- he recalls in flashbacks through a series of boyfriends and disappointments. Her relationship with Nick's dad is yet another blip from which Nick is trying to achieve a life that is loftier.

We know a lot about what drives these people because it's spelled out to us in all-too frequent voiceover -- in dueling narration, actually, as Weitz alternates between Nick's voice and Jonathan's. But ultimately, being either Flynn doesn't seem terribly appealing.

Two stars out of four.