Starring Robin Wright Penn and Alan Arkin. Rated 14A.

How do you keep growing when the persona you've developed is working too well? That's the unusually serious question asked, often movingly, by The Private Lives of Pippa Lee.

Robin Wright Penn plays the title character, now stifled by the solid marriage she built with Herb, an older, very successful publisher, played by Alan Arkin. He's terrific, as always, but Wright is a revelation. She imbues her essentially passive character with inner turmoil that is visible to any sympathetic eye. Unfortunately, Wright's director is not as supportive as one would hope. Working from her own novel, Rebecca Miller has saddled the star with some heavy weights.

First, and worst, the film is drenched in voice-overs—with Wright multitracked and accompanied by syrupy piano plinking—that either add nothing to what we are already seeing or actively take away from the flashbacks, which are already tedious, spending too much time with Maria Bello as the drug-addled mom who drove young Pippa crazy. The other big problem: when the teen Pippa leaves home, in a vaguely set 1970s, she is played by poor match Blake Lively; when she meets a younger Herb, it is still Arkin—doubling what should be a 20-year difference in their ages. (Where was Adam Arkin when they needed him?)

Winona Ryder, Zoe Kazan, and Keanu Reeves are among the other actors who do good work in smaller parts without quite enough help. Miller is both a playwright and a playwright's daughter, and she can be forgiven for feeling a bit too married to her verbal darlings. As a filmmaker, however, she is not quite in control of promising material. Poor Pippa. Such a difficult life, and now this.