Chicago theatergoers have long known Tyla Abercrumbie for her grounded work as an actor in plays like Dominique Morisseau’s Pipeline at Victory Gardens and Lynn Nottage’s Sweat at the Goodman. Her talent as a playwright was lesser known — until February, when TimeLine Theatre Company (of which she is a member) premiered Relentless. Her generational family drama depicts an underexamined slice of American life: the Black Victorian era. Set in 1919 Philadelphia, the play follows two affluent, well-educated sisters tending to the affairs of their late mother, who was born into slavery. A savvy and engaging history lesson, it resonated in a moment when certain forces were renewing efforts to downplay the darker notes in America’s story. Relentless sold out its run at Theater Wit and later transferred downtown for an additional five weeks at the Goodman. Abercrumbie is always a welcome sight on the stage, and now we’re eager to see her next work on the page.