The story starts in medias res. It is June 27th, the day of the lottery. The children assemble first for the lottery. They are excited; what excites them even more is that school just got out for the summer. The men begin to gather next. They talk about work and farming. Finally the women gather and catch up on the latest gossip. At this point the lottery starts. Mr. Summers with a black box comes up to begin. Mr. Graves follows him with a stool, and the box is placed on it. Shortly thereafter, the lottery begins. Some people do not know why they still hold the lottery, but for the most part no one objects. Tradition wins the day. 

All the names are in the box and the lottery begins. Tessie Hutchinson forgot that this was the day of the lottery. So, she rushes. Everyone has finally drawn a slip of paper, and quickly it is found out that the Hutchisons have drawn the black dot. Now the family members draw, and Tessie is chosen. She cries out that it is not fair. As she says this, she is hit in the head with a rock. 

As for what Shirley Jackson meant by this, it is not clear. However, Jackson was interested in magic and witchcraft. She even published a children's version of the Salem witch trials: The Witchcraft of Salem Village (1956). In light of this, Jackson probably liked the macabre theme of the short story. She also probably liked to ruffle people's feathers. In an interview she gave these words:

“Explaining just what I had hoped the story to say is very difficult,” she wrote in the San Francisco Chronicle in July 1948. “I suppose, I hoped, by setting a particularly brutal ancient rite in the present and in my own village to shock the story's readers with a graphic dramatization of the pointless violence and general inhumanity in their own lives.”