“Masked and Anonymous'” greatest asset and its greatest shortcoming are one in the same: Bob Dylan. Set in modern-day America portrayed as if it had been a Third World country, the story, which, rumor has it, Dylan wrote, is built around a familiar iconic cult figure who is liberated from prison just in time to perform in a struggling televised benefit concert for an unknown charity concocted to line the organizers' pocketbooks. That's all about one really can gather from this muddle, other than that impresario Uncle Sweetheart (John Goodman) and producer Nina Veronica (Jessica Lange) need to pull off the event to save their own skins, and journalist Tom Friend (Jeff Bridges) smells a scandal. Starring Jeff Bridges, Penelope Cruz, Bob Dylan, John Goodman, Jessica Lange and Luke Wilson. Directed by Larry Charles. Written by Rene Fontaine and Sergy Petrov. Produced by Nigel Sinclair and Jeff Rosen. A Sony Classics release. Musical drama. Rated PG-13 for some language and brief violence. Running time: 120 min.