Dysfunctional siblings, old wounds from the past, and the search for purpose and fulfillment in one's life are far from novel cinematic topics. And yet, when done well, this subject matter is universal, holding the power to hit a core with viewers who can understand and identify with the characters they see onscreen. "Sunshine Cleaning" misses the mark, not because of what is there, but what isn't. Under the helm of director Christine Jeffs, Megan Holley's first-time screenplay feels half-finished, as if she built the foundation for the plot but forgot to fill in the details. Thus, subplots come and go with little fanfare, relationships lurk just south of being satisfactorily developed, and the tone is too light to hold the dramatic weight it needs to make a lasting impression.

Albuquerque, New Mexico native Rose Lorkowski (Amy Adams) has been out of high school for more than ten years, but she has found herself inadvertently clinging to those glory days when she was head cheerleader and going out with quarterback Mac (Steve Zahn). Now she is a lowly housekeeper struggling to make ends meet for herself and 7-year-old son Oscar (Jason Spevack). She's still sleeping with Mac, all right, but he's married to someone else and has a family of his own. Rose is going to school part-time in the hopes of bettering her future, but when the Oscar is virtually kicked out of school for his eccentric behavior, she decides she needs a way to make good, fast money now. With Rose's younger wayward sister Norah (Emily Blunt) by her side, the two make a go at their own crime scene cleanup business. Facing the physical aftermath of some gruesome deaths, Rose and Norah are faced with memories of their own mother, whose suicide when they were kids has left a marked imprint on their adult lives.

Unsurprisingly, Amy Adams (2008's "Doubt") is sensational in "Sunshine Cleaning," a film that is not equal to the performance she has delivered. As Rose, Adams has the only fully formed character to work with, and she enlivens her with all the complexity one would expect from a protagonist. Hardworking and caring as a mother, but weak-willed when it comes to companions of the opposite sex, Rose regularly goes off to the local motel with Mac despite knowing that there is zero future between them. Cleaning up after grisly crime scenes is not exactly her dream job, but the pay is good and she begins to feel as if she is making a small but indelible impression on those that the victims have left behind. A quiet scene where Rose sits outside with the distraught, elderly Mrs. Davis (Lois Geary) after her husband has killed himself is touching without being sappy and painful in its authenticity. More moments of this nature and less rompish behavior on the job would have been beneficial to understanding the personal gratification Rose experiences in her new line of work.

Emily Blunt (2009's "The Great Buck Howard") is effective in her own right as directionless sister Norah, but less care has been brought to actualizing just what makes her tick. Norah is unable to keep a job, still lives at home with ne'er-do-well freelance salesman father Joe (Alan Arkin), and spends her free time smoking weed when she's not telling nephew Oscar spooky stories before bedtime. We are supposed to believe that Norah's hang-ups stem from her mother abandoning her as a child, but the viewer never receives a real glimpse into who she is and what she wants to do with herself. Blunt and Adams share a late heart-grabber of a scene set in a bathroom, but Rose and Norah do not have enough to do together to really build upon their relationship or the haunting past that left them without a mother.

When Norah comes upon photographs of one of their deceased clients' daughters, she tracks her down under false pretenses and engages in a friendship with the lonely Lynn (Mary Lynn Rajskub). Why does Norah do this? It's hard to say, especially when this story thread whittles out before the end and offers no payoff. The deliciously offbeat Mary Lynn Rajskub (2006's "Firewall") is terrific, more low-key than usual, but Lynn is tossed away by the script before getting closure. The same sort of thing also happens with Rose's burgeoning friendship with Winston (Clifton Collins Jr.), a hardware store owner. How does Winston fit into the bigger picture? He doesn't, outside of being used as a babysitter for Oscar when Rose runs off to a baby shower.

"Sunshine Cleaning" ends on a note of open-ended dissatisfaction. For Rose, at least she has learned to stand on her own two feet and has found her calling, but Norah lacks any arc at all. A shot of her driving down the open highway is a copout that refuses to deal with the bigger issues. Then again, the viewer hasn't really gotten to know her on any substantial level, and doesn't have a clue as to what her future holds. "Sunshine Cleaning" aims to be bittersweet and lighthearted, but its frothy side and unfocused narrative have misplaced the necessary depth needed for the story to take full flight.