Three adult siblings -- Gil (
Steve Martin), Helen (
Dianne Wiest), and Susan (Harley Jane Kozak) -- discover there's more growing up to do as they take on the challenges of parenthood. Gil and his wife (
Mary Steenburgen) have their hands full with three kids, one of whom's suffering from anxiety. Plus, Gil's job pressures weigh heavily on both their shoulders. Helen, a single mom, is battling a headstrong teenage daughter (Martha Plimpton) and a young son (
Joaquin Phoenix) who'd rather lock himself in his room than spend any time with either of them. Susan's husband (
Rick Moranis) thinks training their daughter for the rigors of academia starting at preschool is the way to go, but she's not certain. And with their youngest sibling (
Tom Hulce) arriving out of the blue, Gil, Helen, and Susan, plus their cranky father (
Jason Robards), find that life's about to get even messier.