Finality is staring at Nukain with a big stone face. A black outsider artist in apartheid South Africa, the elderly Nukain has made it his life’s work to turn the rocks on an isolated farm into brightly colored paintings. Now he must tackle the as-yet-undecorated boulder he refers to as “the Big One.” He knows this creative project may be his last.

Such is the scenario at the start of “The Painted Rocks at Revolver Creek,” the undistinguished Athol Fugard play on view in a mostly dynamic MetroStage production directed by Thomas W. Jones II. Benefiting from the magnetic performances of Doug Brown, who plays Nukain, and Jeremy Keith Hunter, who plays the grown-up version of Nukain’s assistant, “Painted Rocks” offers stirring moments and an undeniably affecting conclusion. But the great South African playwright Fugard treats apartheid and South African politics in a much blunter and more spelled-out fashion here than he does in other works. The “Painted Rocks” characters seem not so much living souls as instruments for the parsing of the country’s modern quandary.

This 2015 drama is based on a true story: Fugard drew inspiration from the life of Nukain Mabuza, who decorated stones on a South African farm in the 1960s and 1970s. In Fugard’s rendering, Nukain has an 11-year-old assistant, Bokkie (Jeremiah Hasty), also black, who helps him tackle the intimidating Big One. The result does not impress the farm owner’s wife, Elmarie Kleynhans (Marni Penning), an Afrikaner (South African of predominantly Dutch descent) whose friendliness toward Nukain and Bokkie alternates with condescension and bullying. Two decades later, when the grown-up Bokkie — now known as Jonathan Sejake (Hunter) — returns to the farm, apartheid has ended, and with it, the kind of automatic privilege Elmarie previously enjoyed. Amid painted rocks now bleached by the elements, she and Jonathan struggle to find understanding.

Puttering, and sometimes dancing, amid representations of the Revolver Creek stones, Brown artfully reveals the range of Nukain’s interior life: exuberance, determination, vision, weariness and fear. Hunter is equally arresting as the thoughtful, resolute Jonathan, whose account of a childhood crisis becomes almost dance-like in its animation. (Set designer Patrick W. Lord also devised the projections — waving grain, Nelson Mandela’s release from prison, and more — which play, mostly subtly, in the background.)

Penning is spirited as Elmarie, but the character is written with limited nuance, and the actress doesn’t always succeed in making her more than an idea about a societal phenomenon. Young actor Hasty turns in a decent performance, but the long initial scene between Nukain and Bokkie feels static, partly because Fugard does not make the dramatic stakes immediately apparent.

We do eventually understand the significance of Nukain’s creative duel with the Big One. Even then, it’s hard not to compare “Painted Rocks” unfavorably with “The Road to Mecca,” Fugard’s better play about an outsider artist. As Nukain knows all too well, the problem with artistic achievement is that it becomes a yardstick that subsequent work is measured by.

The Painted Rocks at Revolver Creek by Athol Fugard. Directed by Thomas W. Jones II; light design, Alexander Keen; costumes, Michael Sharp; props, Niell DuVal; sound, Gordon Nimmo-Smith. About 2 hours. Tickets: $55. Through Sept. 30 at MetroStage, 1201 N. Royal Street, Alexandria.