"High Fidelity" and "Annie Hall" meets "The Princess Bride" in "Definitely, Maybe," a romantic dramedy in which a thirtysomething father's complicated past love life is relayed to his daughter via a bedtime story. The dad, a political-minded business type by the name of Will Hayes (Ryan Reynolds), is on the verge of signing divorce papers. This event, coinciding with a sex education class at school, leaves 11-year-old Maya (Abigail Breslin) curious about how her parents met and ultimately got together. Will begrudgingly agrees, turning the clock back sixteen years to find himself a recent college graduate who moves to New York City to work for Clinton's 1992 presidential campaign. As the next five years float by, three women come in and out of his life, any of them possible future mothers for Maya—original back-home girlfriend Emily (Elizabeth Banks), ambitious aspiring journalist Summer (Rachel Weisz), and free-spirited co-worker April (Isla Fisher).

"Definitely, Maybe" is probably a tad smarter than the typical cinematic romance in that writer-director Adam Brooks (2001's "The Invisible Circus") treats his characters as more than caricatures; each one of them has their own hopes, ideas and interests, and feels like a real person. Just because they aren't overblown creations, however, doesn't necessarily make them, or the story they have found themselves in, less clichéd. The plot is shaggy and contrived, the wraparound tale of Will telling Maya about his experiences with love not very believable or organic. That the story being told is so long and detailed, and formed as a mystery—Will intentionally alters the women's names so that Maya won't know ahead of time which one is her mom—leads one to question whether Maya's ultimate bedtime will be after the sun rises.

There are other structural problems with Adam Brooks' screenplay, starting with the central question of which of three women is the one Will had Maya with. Since it is established that they are getting divorced in the present, why should the viewer actively care about the ultimate answer? The ending, which will not be revealed, manages to formulate a happy ending for Will and Maya that does finally resonate, but in order to get to this point one has to slog their way through a lot of labored comings and goings as Emily, Summer and April enter and exit his life over and over again. Because it is exceedingly clear who Will is meant to be with in the long run—something that the daft Will takes forever to realize himself—the film can only spin its wheels for the majority of the running time.

Ryan Reynolds (2005's "Just Friends") is a fine actor, better than he often is given credit for, but his turn as Will seems to be just out of his reach. His performance isn't bad, but it also doesn't command attention or the charm that it should. As curious daughter Maya, Abigail Breslin (2007's "No Reservations") outacts him at every turn, no more so that in a surprisingly poignant moment in the third act between the two of them. As Will's superfluously used best friend Russell, Derek Luke (2007's "Lions for Lambs") mugs far too much for comfort.

Finally, the trio of actresses making up Will's prospective choices—one symbolizing friendship, the other love, and the last his out-and-out soul mate—are memorable with varying amounts of material. Elizabeth Banks (2006's "Invincible") is fetching if underutilized as Emily. Rachel Weisz (2006's "The Fountain") is likable and earnest as Summer. It is Isla Fisher (2007's "Hot Rod"), however, who steals the show as the sweet, down-to-earth April. Spontaneous, soulful and a lot of fun to watch, Fisher is simply electric onscreen, and her chemistry with Ryan Reynolds is palpable throughout.

Every time Isla Fisher shows up, "Definitely, Maybe" sparks to life. In addition to her, it is not the story that intrigues, but the effective background details of the 1990s era. From the first appearance of cell phones, to the infancy of Internet usage, to the Clinton campaign that Will works for, to talk of Kurt Cobain prior to his death, to an establishing shot of Manhattan with the World Trade Center proudly rising above the skyline, to the Monica Lewinsky scandal, the film does a fantastic job of portraying a time and place that, within scarcely more than the last decade, has so wildly been altered. When the viewer concentrates on the plot at hand is when the proceedings stumble. Frankly, it's all been done before, and better. Furthermore, the nearly two full hours it takes to reach its foregone conclusion begins to pry on one's nerves. As a date movie being released on Valentine's Day, one could do a lot worse than "Definitely, Maybe." One could also do a lot better.