Caves can be fascinating, if sometimes dangerous places to explore.

Kevin O’Leary’s “Lascaux,” now having its world premiere run in a production by the Pie Man Theatre, takes the actual discovery of prehistoric cave paintings in France in 1940 as a source point and spins a fictional suspense thriller, set in 1983, that travels deep into the psychology of fear, faith and forgiveness.

While “Lascaux” calls to mind some classic mysteries and flirts with melodrama in a few spots, it ultimately finds its own way as bracing entertainment with a message.

The three-person cast features J.P. Guimont as Marcel, a French official who, as a child, discovered the Lascaux caves with his friend Simon, played by Josh Brassard. Marcel is making plans to cash in by charging admission for people to visit a duplicate of the site when he is surprised by a call from a psychiatrist who is treating Simon at a mental health facility.

Marcel believed Simon died at the time of the discovery and appears concerned about what he may be telling the doctor, named Katherine and played by Mary Fraser, about the events of so many years ago.

The psychiatrist has her own agenda to pursue, as she hopes to get Marcel to use his connections to help get renewed funding for the facility. Amid flying romantic sparks with Marcel, she frets that she may have become too devoted to things other than treating Simon, whose illness has him endlessly recreating the cave paintings and speaking in mysterious ways.

Director Stephanie Ross has brought out an impressive level of commitment from the actors and, with her design crew, has created a truly suspenseful ambiance, including spooky lighting and quickly alternating changes of scene. A little high school-level French is employed to add flavor.

Though his hushed vocal tone may reveal his character’s trajectory a little early, Guimont manages to have his Marcel insinuate himself into the minds of the others (and the audience) by creepily focusing on his “strength” and “glory.” Some business about the lining of his coat and other quirky details provide the veteran actor with some choice opportunities to snarl.

Fraser has her Katherine, with secrets of her own emerging, balance the mix of professional and personal motivations that the author has given her. The actress realizes her ultimately sympathetic character in a subtly emotive performance that fits the intimate three-quarters-in-the-round theater space well.

Brassard’s Simon, through obsessive movement and speech patterns, becomes an unpredictable but touching innocent. His haltingly delivered verbal repetitions give the work a poetic dimension that provides an approach to the stylized cave paintings reproduced in a large onstage mural by the author’s artist son, Brian O’Leary.

Will they all “return to the light” or remain forever in the “realm of sorrow”? Find out in an imaginatively conceived and executed evening of theater.

Steve Feeney is a freelance writer who lives in Portland.