Racso and the Rats of Nimh

This is the second book in the Trilogy of books in the Nimh series. But it didn't matter to me because I know the original story. Racso learns of the rats of Nimh from his father. When he is old enough he travels to Thorn Valley where the rats live in a secret community. He wants to learn to read and write. On the way on his journey, he encounters Timothy Frisby. After making it to Thorn Valley he goes to school for a few months. He learns to write and makes some friends. Then the rats find out that the humans are building a dam that will flood the valley. They move some supplies to a secondary location. Then they come up with a plan to make sure the dam is destroyed so they can keep their home.