The insistent emotionalism of August Wilson's plays is sufficient to compel an audience's attention, but his gift also extends to a mastery of common language lifted to eloquence. Now on stage at Geva Theatre in a strong, lively ensemble production, Wilson's Gem of the Ocean was first performed in 2003, but takes place in 1904. It comes first in his 10-play cycle about the African-American experience in the 20th century. Its performance marks the beginning of Geva's laudable five-year undertaking to present all 10 plays as performances or staged readings.

It is important to honor Wilson, who died in 2005 at 60, but just as important to note his shortcomings. Despite the frequent authority and humor in his writing and the conviction of Geva's cast, Gem of the Ocean announces its themes rather than dramatizes them, falls back on bromides at crucial moments, and relies on a jumble of incidents to wrap everything up at the end. No matter how riveting the characters' struggles and confrontations often are, two and a half hours is a long time when the play's wisdom rarely avoids banality: "You've got to be right with yourself before you can be right with anybody else."

As usual, Wilson sets his story in the Hill District of Pittsburgh, in the house of ancient Aunt Ester, who admits to being almost 300. Through Ester, Wilson's steadfastly realistic work crosses into "magic realism" because she is a worker of trances that dissolve time and reanimate the past. Unfortunately, the climactic trance scene that transforms young Citizen Barlow into a slave crossing the Atlantic to a vividly described "city of bones" feels contrived and self-conscious. Yet Lizan Mitchell's performance as Ester is otherwise rich with sympathetic insight.

The plot line is clear even though it portrays complex people struggling to make peace with themselves: Barlow, recently arrived from Alabama, comes to see this "washer of souls" because of the guilt he carries. His coming to be cleansed is set against a strike carried out by the black employees of a mill when one of them dies after being accused of stealing nails. The worker chose death rather than being labeled a thief for a petty crime he did not commit.

Among those "Mr. Citizen" meets is Solly Two Kings, old enough to have been an escaped slave and then a conductor on the Underground Railroad. He is about to leave for Alabama to rescue his sister because Jim Crow laws have recently tightened.

Ester's longevity and her magical powers enable her to embody the history of her people and eventually pass it on, but Solly's own story gives it immediacy. All of Wilson's plays have these interwoven digressions, which often deepen the play's central concern. Solly's is a rich ride on America's racial history that gathers force from the notched walking stick he carries, each notch another slave he helped to escape. Ernest Perry, Jr. conveys Solly's vitality, humor, and determination. Among the other performances, Chris Chalk's Citizen is disarmingly open, and Richael Leslie illuminates housekeeper Black Mary's change from sulking servant to independent woman. Only David Alan Anderson as an unsympathetic policeman struggles with an underwritten part that relies on melodramatic posturing.

Timothy Douglas' direction embraces the play's emotional heart, but Tony Cisek's overly large set distracts from its centerpiece, the dining room table where almost everything transpires.

The struggles of Wilson's characters to find inner peace so that they can struggle bravely in the world is ultimately what gives Gem of the Ocean life. It is also something that Geva Theatre's cast understands and serves.

Gem of the Ocean | through April 29 | Geva Theatre Center, 75 Woodbury Boulevard | $14.50-$53.50 | Geva will present a staged reading of the second play in Wilson's 10-play cycle, Joe Turner's Come and Gone, Monday, April 23, at 7:30 p.m.; tickets are free, but reservations recommended | 232-GEVA | www.gevatheatre.org