This feels different from ‘I have a great idea’. It implies that you’ve studied the market very hard and have found a space on the bookshelves which you intend to fill or die in the attempt. Your story is called Ernie the Line-Dancing Earthworm. Scissor kicks, invertebrates: this baby has it all! You haven’t thought about the writing or illustrating part yet, but you feel confident that these are secondary to the originality of your concept.
You’re on dangerous ground. There are only a finite number of plots, and they’ve all been done. Anything that remains, generally remains unwritten for a good reason.
Georges Polti states that there are thirty-six plots in his book, Thirty-Six Dramatic Situations (1916). Christopher Booker’s The Seven Basic Plots (2004) claims, unsurprisingly, only seven. Other theorists have declared that there are just two stories: going on a journey, and a stranger coming to town. Which you could argue is the same plot really, just seen from the opposite direction. Anne Fine, prize-winning author and Children’s Laureate 2001-2003, has said that “plots are overrated,” and she may have a point.
Great children’s books can be about nothing at all, and yet everything at the same time. The story that will succeed is not the madly original idea; it’s the brilliantly well-constructed one.