Okay kiddo, a light plot is like a map for a play or performance that shows where all the lights will be placed on stage. It’s kind of like a drawing that shows a bird's-eye view of the stage and where all the lights will be shining from.
The people who work on making the play look really cool are called lighting designers, and they use the light plot to help them plan where they will put all the lights so that they make the actors and stage look just right.
You know how when you use a flashlight, you can point it in different directions and it changes the way things look? It’s the same idea with stage lights, but the lighting designer has to think about all the different parts of the stage and make sure everything looks good from every angle.
So they use the light plot to make sure they have all the right lights, in the right places, shining in the right direction, at the right time. It’s like a big puzzle they have to solve so that the play looks amazing when you go see it.