Frowzy, acid-tongued, supporting herself and her two daughters by taking in a decrepit old boarder, Beatrice Hunsdorfer wreaks a petty vengeance on everybody around her. One daughter, Ruth, is a pretty but highly strung girl subject to convulsions; while the younger daughter, Matilda, plain and almost pathologically shy, has an intuitive gift for science. Encouraged by her teacher, Tillie undertakes a gamma ray experiment with marigolds that wins a prize at her high school -- and also brings on the shattering climax of the play.

Proud and yet jealous, too filled with her own hurts to accept her daughter's success, Beatrice can only maim when she needs to love and deride when she wants to praise. Tortured, acerbic, slatternly, she is as much a victim of her own nature as of the cruel lot that has been hers. And yet, as Tillie's experiment proves, something beautiful and full of promise can emerge from even the most barren, afflicted soil. This is the timeless lesson of the play and the root of its moving power and truth.