When 10-year-old Maya (Abigail Breslin of Little Miss Sunshine fame) pesters her dad Will (Ryan Reynolds, best known for his roles in National Lampoon's Van Wilder and Blade: Trinity) to explain the birds and the bees, he sidesteps the nitty-gritty of human anatomy.
Instead, he tells her about the three women in his life, giving them assumed names and asking Maya to guess which one is her mother.
As her parents are getting a divorce, Maya knows there's no happy ending to the story, but becomes engrossed nonetheless.
At the heart of the Definitely Maybe's love mystery are the three very different women: blonde high school sweetheart Emily (Elizabeth Banks), perky political campaign copy girl April (Isla Fisher) and sexy intellectual Summer (Rachel Weisz).
Told by Will in a series of flashbacks, the break-ups and reunions are played out in New York City against the backdrop of an election campaign and the subsequent tumultuous presidencies of Bill Clinton, without ever resorting to melodrama.
Director Adam Brooks handles the on-and-off love affairs with such deftness that you can't help rooting for the hapless young man when he's down and out in both love life and career.