Not to be confused with the short-lived but deservedly acclaimed 2004-2005 television drama of the same name, "Life as We Know It" is about as fresh as its title. The premise is one big sitcom-style contrivance, a pitfall that director Greg Berlanti (2000's "The Broken Hearts Club: A Love Story") and first-time screenwriters Ian Deitchman and Kristin Rusk Robinson do little to circumvent. Katherine Heigl (2010's "Killers") and Josh Duhamel (2010's "When in Rome") are amiable, attractive leads, but they, too, are at the mercy of threadbare writing and a tired story that goes exactly where you expect it to. In years to come, "Life as We Know It" may be used as a prime example of "mediocre" in Merriam-Webster's updated dictionary.

Three years ago, Holly Berenson (Katherine Heigl) and Eric Messer (Josh Duhamel) were set up on a disastrous blind date by respective married best friends Alison (Christina Hendricks) and Peter (Hayes MacArthur). They have barely been able to tolerate each other ever since, but must suddenly try to set their differences aside when tragedy strikes and the two of them learn they have been named as shared legal guardians of Alison's and Peter's one-year-old daughter Sophie (played by triplets Alexis, Brynn and Brooke Clagett). In another convenient development, they get to keep their late friends' lovely suburban home and move into it. Holly and Messer—he goes by his last name, natch—have no experience raising a child, but aren't about to turn their back on Sophie and her parents' wishes. As they struggle with sudden newfound parenthood, Holly and Messer draw closer, discovering neither is as bad as the other thought.

Because of its solid cast, "Life as We Know It" isn't the utter chore it might have been. Instead, it's merely bland, derivative and slightly annoying. The characters are given whimsical "movie" professions (she owns a quaint bakery and he's a technical director for the Atlanta Hawks basketball team). The characters' names are so liberally peppered into dialogue that it may drive slightly off-kilter viewers over the edge into insanity ("Messer" is uttered at least once per minute). Complications arise in the form of a possible nice-guy suitor for Holly, handsome pediatrician Sam (Josh Lucas), and a job promotion for Messer that will potentially relocate him to Phoenix. Jokes about changing dirty diapers, getting thrown up on, and convincing little Sophie to eat come with the steadfastly predictable territory. Harried Child Protective Services worker Janine Groff (Sarah Burns) keeps showing up unannounced and at the most inopportune of times. Arguments and falling-outs typically occur when lots of people are around to watch or listen in. Oh, and wouldn't you know it, there's even a climactic dash to the airport for Holly as she tries to catch Messer before his flight leaves.

Katherine Heigl always seems much quicker and savvier than the films she is in, and this is definitely the case here. Heigl brings some levity to Holly by portraying her as caring of Sophie but in over her head, but she's still stuck in a patently manufactured plot. As Messer, Josh Duhamel passably plays the unreliable ladies' man who grows up himself as he raises Sophie. They become romantically involved out of the conventions of the script, not because their romantic relationship ever feels natural. One woebegone dramatic scene is rendered especially inappropriate by having Heigl and Duhamel argue while wearing painted cat faces. Josh Lucas (2006's "Poseidon") is saddled with the thankless role of "other guy" Sam, who, despite sharing more chemistry with Heigl than Duhamel does, hasn't a chance in hell at getting the girl by the end. Meanwhile, Melissa McCarthy (2010's "The Back-Up Plan") brings a sassy, southern-spun charm to neighbor DeeDee, and Sarah Burns (2010's "Going the Distance") steals the show from everyone else around her as quirky, exceedingly involved social services worker Janine. Burns is a hoot whenever she's on the screen; a film centering on her character would have been preferable to this one.

Primarily set over a twelve-month period marked by each of the four seasons, "Life as We Know It" concludes with Holly and Messer having survived their first year as adoptive parents while overcoming obstacles to fall in love. The outcome is an obvious one when something less orthodox would have certainly come as a welcome respite. Furthermore, the viewer is left pessimistic about the future of Holly and Messer as a couple since they never would have gotten together were it not for living in the same house and co-parenting Sophie. This convenient little setup might be life as they know it, but for the rest of us every last development is strictly informed by the false realities of cinemaland.