In this sequel to Mrs. Frisby and the Rats of NIMH , Rasco, a boastful rat, is trying to find his way to Thorn Valley, the home of the intelligent rats of NIMH, to learn to read and write. On his way, he meets Timothy Frisby, a field mouse, who joins him. The two arrive in Thorn Valley only to discover that it is threatened by Humans--and it is a true test for Rasco and his bragging to try and save the town.