Louis Ives (Paul Dano) is a young would-be novelist who's fond of "The Great Gatsby" and might have stepped out of its pages. With his gentlemanly demeanor, Louis would have been right at home in the 1920s. Unfortunately, he's stuck in contemporary New York, sharing a dingy apartment with an aging misanthrope named Henry Harrison (Kevin Kline).

Once a promising playwright, Henry has become an escort to elderly, wealthy women — an "extra man," as he puts it. But as much as he enjoys hanging out in high society, he's also disdainful of his lot in life.

In contrast, Louis is open to just about anything, including the possibility of a romance with office acquaintance Mary (Katie Holmes), who's as ordinary as Henry is eccentric.

Louis has a lot to learn, and Henry could be a valuable source — if they can tolerate each other long enough.

Based on a novel by Jonathan Ames and scripted by Ames and directors Shari Springer Berman and Robert Pulcini, "The Extra Man" puts the emphasis on quirkiness. To that end, Kline, who won an Oscar for his offbeat supporting performance in "A Fish Called Wanda," is a definite asset. But his efforts can't compensate for the episodic story, which moves so slowly that it undercuts the comedy.

It's left to Dano, who has appeared in films such as "Little Miss Sunshine" and "There Will Be Blood," to lend the movie a much-needed warmth and humanity. His performance is so sympathetic that it almost makes up for his underwritten character. And Holmes is effective as the shallowly appealing Mary.

"The Extra Man" is a disappointment coming from Berman and Pulcini, whose "American Splendor" (2003) was an imaginative biopic about the late comic-book author Harvey Pekar. Although their latest film is not without a certain charm, it quickly wears out its welcome.