The first big lie is that 15-year-old Thomas (Tobias Segal) hasn't been honest with 32-year-old lawyer Carla (Karina Arroyave) about his age, which puts them both in a pickle when she discovers she's pregnant. The news doesn't sit well when Carla -- who dumped Thomas on learning the truth about him -- arrives for a round of bean-spilling to his mom Julia (Summer Crockett Moore) and to his maternal grandmother Teresa (Joanna Bayless).
Thomas' mendacity can be traced to disorientation caused by his parents' divorce, although neither Julia nor her ex-husband Arthur (Jim O'Connor) will explain to Thomas why they split. Not willing to take no for an answer after three years of badgering both Julia and the bigoted and misogynistic Arthur, Thomas finally gets Arthur to blurt out the reason -- or some of it. That's better than in-the-dark Teresa does at finding out why Julia married Arthur in a hurry and then refused to see her mom and dad for 12 years.
Needless to say, the secret of Julia's extended absence is eventually vouchsafed within Teresa's earshot and, as a result, further estranges everyone from everyone else. At this crazy-mixed-up point, Glazer's concern becomes how do all these stained characters out-out themselves of those damned emotional spots? Will Julia and Teresa reconcile? Will Thomas continue to live with Arthur? Is it fair of Carla to expect Thomas to support their expected child but never see him/her? And who is that man in the photograph with Teresa on the wall?
But the real question on a viewer's mind will be why Glazer takes so long to have one of his frustrated figures reveal Julia's tenaciously-held final secret when most of the audience has already guessed it and why after he unleashes his last (ho-hum) shocker of a family secret, does he keep the quintet coming back for more set-tos. Actually, it's a sextet, since Thomas' friend George (Peter Brensinger) is superfluously hauled into the mix for two scenes meant to make a case for Thomas' being just a typical teenager. Sadly, Stain is just all too typical of a second-rate dysfunctional family drama.