Set in small-town Alabama in 1900, it’s based on Lillian Hellman’s 1939 play “The Little Foxes.” There is nothing remotely amiable about Regina Giddens: She’s cold, calculating and capable of doing whatever it takes to get whatever she wants — and her wants are boundless. Her brothers, Ben and Oscar Hubbard, whose specialties are sharp dealing and prevarication, commit the signal error of underestimating her.

In the title role, mezzo-soprano Susan Graham (who usually portrays amiable characters) is an imperious force of nature. It’s a demanding role, with an unusually wide vocal range to go with its daunting dramatic requirements; she nailed it in every respect, singing powerfully with acting to match.

The rest of the cast, headed by three other distinguished artists, was equally remarkable. Soprano Susanna Phillips was touching as Birdie, the music-loving daughter of Southern aristocracy whom Oscar married so that Ben could get her family plantation, Lionnet; her third-act aria was heartbreaking.

Bass-baritone James Morris, making his OTSL debut, gave a subtle performance as Ben, who maintains an ironic sense of humor and spins ways to put the blame on others. As the less-subtle Oscar, baritone Ron Raines was a well-matched third sibling.

Soprano Monica Dewey easily held her own in this distinguished company as Alexandra, “Zan,” Regina’s daughter, singing beautifully and maturing as we watched. As her father, the ailing Horace Giddens, bass-baritone Kristopher Imiter brought a weary dignity to his role.

Addie, the Giddens family housekeeper and a beacon of decency, was sympathetically portrayed by mezzo-soprano Melody Wilson; tenor Michael Day was appropriately slimy as the young and amoral Leo Hubbard. Chaz-men Williams-Ali shone in the (mostly off-stage) role of Jazz; Robert Stahley created a solid character as William Marshall, the businessman from Chicago.

There were no weak links in the large cast; Cary John Franklin’s chorus sang (and danced Sean Curran’s choreography) well. In the pit, music director emeritus Stephen Lord made an excellent case for the score, with the help of the St. Louis Symphony Orchestra.

Artistic director James Robinson brought out the family’s fraught dynamics effectively in ways both large and subtle; having Addie depart with Alexandra at the end was a nice touch. Allen Moyer’s set, dominated by a giant painting of Lionnet and a long staircase, was marred by walls of mottled gray, like the inside of a bunker. James Schuette’s handsome costumes were true to the period.

Although the singing is unamplified, having music under much of the dialogue necessitated miking it. There was a problem with the sound system on Saturday night, which resulted in a lack of balance at times.