Underneath's moral seems to be that all humans are inherently flawed and evil. With a great deal of symbolism that, on one hand indicating a lot of depth in conceptualisation, and on the other hand indicating someone running amok at the helm of this movie, Underneath manages to deliver its message in one of those flashback-movie styles which has almost become cliche.
The flashback scene is essentially is about a compulsive gambler Michael Chambers (Peter Gallagher), who left his now ex-wife, Rachel (Alison Elliot), holding the shitty side of the toilet paper after losing a bet which puts him in great financial burden. Years later, as his mother is getting married again, Michael returns to his home town to find Rachel engaged to a local "Mack-the-knife", Tommy Dundee (William Fichtner). Then we have Michael's brother David (Adam Trese), a policeman, who secretly loathes Michael and divulges this information only when Michael's in the hospital. Combine this with a plot to steal money from an armoured-car cash delivery service with the help of the mysterious Broker intermixed with sexual tension between various parties, you have essentially a movie that at best leaves you mildy confused but still convinced it is good, or at worst, simply dull.
There is a lot of symbolism in this movie: Lottery numbers being picked in the TV, Rachel wanting to be a Vanna White clone, two security guards gluing a jigsaw puzzle together, satellite dishes, and out of perspective blurry pictures. I particularly found the depiction of Michael's state of mind as he watches the football game that he bet on excellent. I also though the guise of Michael's kidnapper was convincing. William Fichtner as Tommy Dundee makes for a good villain. All these are put together well---at least enough so the viewer is left in some doubt as to what is going to happen next. What more do you need?
"I can't believe you wore dad's suit to mom's wedding."