"The Greek tragedies of Aeschylus begin with a single action, a single mistake -- the 'original sin'. It is the seed from which the story grows ... Someone makes a mistake in the past. What happens when that mistake changes history so much that it informs everything that happens over the next 20 years?"

And so writer and director Dan Harris describes his motivation for "Imaginary Heroes" a leaden new family drama starring Sigourney Weaver and Jeff Daniels.

While we aren't at liberty to disclose the "original sin" in the film, you can rest assured that Harris has stuck quite close to Aeschylus' script. Matt Travis (Kip Pardue) is a trophy-winning swimmer. The trouble is he hates swimming and that his dad, Ben (Daniels) is a confirmed stage dad and taskmaster when it comes to Matt and the sport.

So, when Matt takes his own life, everyone pretty much assumes it was the stress of that situation that was behind this desperate act. But we get the feeling his younger brother Tim (Emile Hirsch) knows something more about it. Neglected by his dad, Tim is the artistic outsider in a teetering family that crumbles after Matt's suicide.

Their mom Sandy (Weaver) is a wreck and Dad has ceased to function and relate to anyone else in the house (there's also a college-age sister, Penny, who pops in and out of the story).

Tim's sole source of comfort is his best friend and next door neighbor Kyle (Ryan Donowho), whose mother Marge (Deirdre O'Connell) is embroiled in some sort of feud with Sandy and that feud, early on, creates some of the light-hearted moments that keep the film from sinking into a depressive muck.

In true Greek tragedy style, everything will come to a head and all of it can be traced back to a single incident that occurred almost 20 years ago. If you're looking for a spoiler, look elsewhere.

Despite any preconceived notions we might have about the cast, everyone does a fine job with a well-written script that, thankfully, has some lighter moments to balance things. Weaver and Hirsch are especially engaging and the film -- a deep exploration of family, belonging, tragedy and regret -- really belongs to them.

"Imaginary Heroes" opens Friday, April 15 at Landmark's Oriental Theatre.