Tom and Kate Baker are the parents of twelve children. They live in a small town and although their life is very busy, everyone seems happy. Tom is a football coach at a small college but dreams of a job at a big university. One day Tom gets a job offer at a bigger college in Chicago and takes the job. His kids are upset about his decision because they don’t want to move to a new place.

In the meantime, Kate had written a book about having a big family. Soon after the move to Chicago, she learns that she must leave the family for a short time and go on a book tour to promote her new book. Tom encourages Kate to go because he thinks he can handle his job and all the children at the same time.

The children, however, have other plans and become rebellious, making all kinds of trouble for dad and each other. Tom asks his oldest daughter to return home to help him manage the family. She brings her boyfriend with her and the kids prank him. Rather than making things better, this makes things even more chaotic.

While Kate is still on the book tour, she finally learns that things are not well at home and she cancels her book tour and returns home. In order to continue promoting the book, her publisher decides to invite a famous TV celebrity, Oprah Winfrey, to do an interview with Kate at the Baker’s home. Unfortunately, even Kate can’t seem to pull the family back together. The TV crew see the chaos and advise Oprah to cancel the TV interview.

During all this commotion, Mark’s pet frog dies. Mark is one of the siblings who already feels like an outsider in his family. Mark is upset and feels he has no one to turn to, so he runs away. The family all go looking for Mark and the father finds him. This brings the family closer together and causes everyone to reconsider their priorities, especially Tom. So Tom decides to quit his job as a coach at the big college and find a job that will allow him more time for his family. Kate’s book becomes a best seller, and the family returns to normal… well, as normal as any large family can be.