Is there a sequel to Mrs. Frisby and the Rats of NIMH?
"Mrs. Frisby and the Rats of NIMH" was written by Robert C. O'Brien (a pen name of Robert Lesly Conly 1918-1973). This book was later reissued under a new title, "The Secret of NIMH" when the animated film of the same name was released. O'Brien's daughter, Jane Leslie Conly wrote two sequels, "Rasco and the Rats of NIMH" and "R-T, Margaret, and the Rats of NIMH."
Mrs.Frisby and the Rats of Nimh is a book wrote by an author named Robert C. O'Brien who lived from 1918 -1973. If you want to know what the story is about, then go to Google and type in "What happened in the story Mrs. Frisby and the Rats of Nimh" or type in "Summary for Mrs. Frisby and the Rats of Nimh
In Chapter 13 of Mrs. Frisby and the Rats of NIMH (A Powder for Dragon) Mrs. Frisby is still shocked about the rats and their sophisticated advancements. She also learns that the rats put sleeping powder in Dragon's bowl to enable them to 'work' which causes Mrs. Frisby to recall her seeing the rats move a cable into their rosebush/cave.