Green Grow the Lilacs is a one-act play, set in early twentieth-century Oklahoma, that combines music and drama to tell the story of a love triangle between the cowboy Curly McClain, the beautiful Laurey Williams, and the murderous hired hand Jeeter Fry. The play is unique in that it consists of only one act and six scenes.

In the first scene, Curly, a young cowboy, is outside a farmhouse singing a song. Aunt Elly hears him and invites him inside. After few more songs and some jovial chatter, Curly tells Ella that he has come to invite Ella's beautiful eighteen-year-old niece Laurey to a party at Old Man Peck's house. Much to Curly's disappointment, Laurey comes down to tell him she is already going to the party with the family's hired hand Jeeter.

In the second scene, Aunt Ella is helping Laurie get ready for the party and chatting to her about Curly and Jeeter, when they hear a gun shot from the smoke house.

Scene three takes place at the same time as scene two. Jeeter and Curly are playing cards. Curly is being his usual jovial self, singing songs, but Jeeter is telling stories about murdering girls. The tension increases when Jeeter interrogates Curly about why he was at the farmhouse earlier. When Curly eventually admits his interest in Laurey, Jeeter seizes his gun and shoots at the back wall. Moments later, Laurey and Aunt Ella are running through the door.

Their rivalry increases in scene 4, at the party, and boils over in scene 5. In scene 4, Laurey becomes scared of Jeeter and fires him from his job at the farm before running away to find Curly. Seeing his chance, Curly asks her to marry him, and she accepts.

Jeeter though is now looking for revenge. After their wedding, in scene 5, Curly and Laurie participate in an old Oklahoma custom where the villagers force the couple into a hay barn and throw straw dolls at them. Jeeter sees this as his chance and sets fire to the straw. Curly and Laurie escape, but in the subsequent fight between Curly and Jeeter, Jeeter falls on his knife and dies. The scene ends with Curly deciding to give himself up to the police.

In scene 6, Curly escapes jail the day before his hearing, to spend the night with Laurey. Men pursue him to the farmhouse, but Aunt Ella convinces them to let the couple finally have their wedding night.