Just suppose that you have guests for dinner, there’s a lot at stake on the evening, and it’s just a trifle tense in atmosphere. Suddenly, without warning, a man you don’t know enters your apartment, says he’s been mugged, claims to know your children, and then collapses from a knife wound to the stomach. What would you do?

If you are Flanders Kitteridge (David Sennett) and his wife Louisa (Leonore Field), you give the youth a room, bandage his wounds, give him a new shirt that is one of your son’s, and sit down and listen to his story.

Never mind that it is a fantastic one. He has established his bona fides with intimate details of your life and children, claiming he knows them from Harvard. And after his sudden appearance seems to shatter your evening, he does everything in his power to save it for you — including making you a sumptuous dinner. And the business that is to be settled over dinner is done positively, so everything is well — in fact, Flan and Ouisa are giddy over the evening and the sudden appearance of this generous youth, who saved a deal Flan only dreamed would take place. This young man Paul (J. Alphonse Nicholson) turns out to be a lifesaver, and all go to bed in a fog of giddy well being.

This is the opening scene to John Guare’s Six Degrees of Separation, a study of the effects of being hoodwinked by a con man and what it does to a family. It is the latest production of Ghost and Spice Productions’ 2010-11 season, and it runs through October at the Common Ground Theatre in Durham. Director Rachel Klem sets the play on a multi-level set designed to contrast the multiple characters that are portrayed by the rest of the cast: three apiece by Larry Evans, Mary Cates, and Amanda Watson, and a whopping six by chameleon Aaron Dunlap. This is an aspect of the “small but mighty” design that is the Ghost and Spice trademark.

While it is entertaining to witness the interchange of all the multiple characters onstage, done so well by this cast, the change that is manifest in Flan and Ouisa begins to tear the two apart. Having lived well, but above their means, for quite some time, the deal that was closed that evening makes Flan and Ouisa comfortably well off for the first time. And this makes Ouisa a bit ambivalent over Paul, who did not steal anything from them but their peace of mind. Flan, on the other hand, has no such compunctions, and is ready to have the lad in handcuffs.

As the show progresses and they learn more and more about how many people they know who have been scammed by this youth, Ouisa makes Paul her project. She decides, ultimately after a telephone call from Paul begging forgiveness, to try and “save” him from himself. She promises to come get Paul and bring him to the police, where he will turn himself in. But he is arrested by the police before Ouisa and Flan can get to him, then he is lost in the system so Ouisa loses him in the maze. He is not heard from again.

Guare’s tight and swiftly moving play seems to leave us with the notion that we never really know anyone, despite how long or intimately we think we do. Ouisa explains that, between any two people, there are only six degrees of separation: a total of six people separating the two. The insanity, says Ouisa, is finding which six.

There are undercurrents and interrelationships that are complex and hilarious in this play, most especially between the adults and their nearly-adult children. But the real relationship that counts is the one between Ouisa and Paul — and also the one between Ouisa and Flan. There is the possibility that Paul has committed suicide in prison; Ouisa will never be sure of the fact but, it is clear, she blames Flan for it. Their relationship will never be the same. It is perhaps what Paul has ultimately taken from them — their complacency. One wonders if the Separation of Guare’s title is not ultimately the one that will soon take place between Ouisa and Flan. It is clear that some degree of separation has already occurred there.

Six Degrees… continues through October 23. For details, see our calendar.