Oscar-winning screenwriter Aaron Sorkin (The Social Network) makes his directorial debut with Molly’s Game, which is based on the life of so-called “Poker Princess” Molly Bloom (Jessica Chastain), a former Olympic skiing hopeful who turned to running high-stakes, celebrity-studded underground poker games in Los Angeles and New York after an unfortunate wipeout on the slopes during an Olympic qualifying run dashed her gold-medal dreams. Her story, told in a series of flashbacks after she’s arrested by the FBI, is crammed with Sorkin’s trademark rat-a-tat dialogue, which Chastain delivers with ease and artful finesse. Her dynamic, compelling performance is the best thing in the rookie helmer’s intriguing but bloated film. Most of the flashbacks occur as Bloom explains her complicated story to her lawyer, Charlie Jaffey (Idris Elba, fine and formidable). We gain some insight into her difficult childhood and love-hate relationship with her demanding therapist father (a strong-willed Kevin Costner), who pushed her to be an Olympian. After her tragic injury, Bloom postpones going to law school and moves from Colorado to Los Angeles, where she is quickly introduced to the world of underground poker. She isn’t a player, but she works for a rich sleazeball who runs a weekly game that is attended by an assortment of Hollywood A-listers. The movie, just like Bloom’s memoir, doesn’t use the real names of the Tinseltown regulars, but it’s understood that these men are part of the “exclusive, decadent man club,” and are not only high rollers, but high up the food chain in entertainment, sports, and business. (It’s no secret that Leonardo DiCaprio, Tobey Maguire, Matt Damon, and Ben Affleck were among the attendees.) When Bloom sees a chance to steal the game away from her boss after he stupidly cuts her pay, she takes it, and elevates and expands the games to a whole new luxurious level that attracts even more upscale players. But after a decade of glitzy success, it all comes crashing down when she reluctantly gets involved with Russian mobsters and starts taking a percentage of the pot -- a big no-no. Soon, she’s hauled off to jail for running an illegal gambling operation. Sorkin is great at writing individual scenes that sparkle with wit and intelligence, and that provide plenty of rapid-fire inside information (sometimes too much) on everything from mogul skiing and poker hands to legal maneuvers and real estate. Not all of it is understandable, but Sorkin doesn’t care if we can take it all in or not. What’s important is that it’s entertaining and propels the story forward in a mostly engaging fashion. The movie does lose some steam late in the game, especially during an awkward, extended scene between Bloom and her dad in which he tries to explain her motives for the questionable choices she’s made. It’s one of the film’s only intimate scenes, but it comes too late and doesn’t go far enough. Sorkin continually keeps the spotlight on Bloom’s business dealings and legal woes, and almost entirely ignores her personal life, which at one time included heavy drug usage. She also bankrolled the games, vetted the players, and extended credit -- all of which were extremely stressful, as the real-life Bloom has made known in countless interviews. But Sorkin doesn’t go down that path. Perhaps another director would have insisted on keying in on Bloom behind closed doors to add depth to her character, but sadly, Sorkin does not. Poker enthusiasts looking for some high-stakes action will be sorely disappointed: The games aren’t what excite Sorkin. Artful dialogue and getting great performances from his actors are what count here, and on those points Molly’s Game delivers a winning hand. Overall, the movie is more of a full house than a royal flush. It’s a sure bet that both Sorkin’s script and Chastain’s stellar performance will deservedly garner Academy Award nominations. But if you’re a gambler, don’t go all in on them walking away at the end of Oscar night with any hardware in their hands.