Take two couples with different backgrounds. Make them back yard neighbors. Step back and see what happens.

What happens in Lisa D’Amour’s dark morality play is the collision of cultures resulting in the two couples bringing out the worst in all four people.

Ben (David Rabinow) and Mary Melissa Pennicj) live a quiet life in a Detroit suburb. She’s a paralegal with a drinking problem. He’s unemployed with the hope of making it big on the Internet.

Kenny (David Tessier) and Sharon (Clara Weishahn) move next door and are invited over for a cookout. There’s something off-center and mysterious about the new couple. They have no furniture. They tell conflicting stories about how and where they met and what they do.

Backgrounds and lifestyles conflict, yet the two couples bond in a strange way. Little things bother Mary, and boy does she have problems dealing with the bigger things.

As the couples spend more time together, they confide in each other, eventually letting it all hang out. Inner thoughts and feelings are revealed, with the new couple influencing the other couple to let loose, enjoy life and quickly move toward a scary and destructive conclusion.

Is this a morality play? Is this an indictment on society? D’Amour leaves it for us to decide, as a fifth character shows up to pick up the pieces and shed some light on the situation.

“Detroit” is a strange but compelling play. People will take different things from it, depending on where they are on life’s journey.

Director Josh Short has turned their site of Trinity Rep’s first stage around, so that the audience has its back to the stage, creating two back yards.

The cavernous space provides one problem: Voices are often lost, especially when the actors are not in front of you or have their back’s turned. Perhaps a louder projection or slowing the execution down a bit would help those of us who have to strain to catch every word.

The acting is good in this one-act 90-minute play that will leave you with much to think about.

“Detroit” is at Wilbury Theatre’s new space at 393 Broad St. in Providence. Call 400-7100 for reservations. Tickets are $20.