Robert Downey Jr . is making plans to fill the fall hole in his schedule with the lead role in Inherent Vice for writer-director Paul Thomas Anderson . Anderson has been working on a screenplay adaptation of the 2009 Thomas Pynchon novel while trying to get another film -- an untitled exploration of a religious organization sometimes referred to as The Master -- off the ground. Once Downey dropped out of Disney's Oz, the Great and Powerful last month, it freed him to do another movie later this year after he shoots The Avengers for Marvel and Disney. His commitment to Anderson's movie has recently grown serious. Vice is a comparatively accessible Pynchon work that tells the story of a stoner detective who gets wrapped up in a number of mysteries in 1969 L.A. while the Manson Family trial growls in the background. Downey, who last starred in Due Date and Iron Man 2, has wrapped filming on Sherlock Holmes: A Game of Shadows for director Guy Ritchie and Warner Bros. T...