

The children try to keep the secret of Thorn Valley, but after pressure, Margaret ends up revealing it.

However, when winter comes, the rats cannot shelter the children and must send them back. The children help the rat community with various tasks, and Artie and Christopher become very close friends. When two children, Margaret and her younger, autistic brother Artie ("R-T"), are lost during a camping trip, they are found by the colony of rats, specifically one named Christopher. O'Brien), the author of the original Rats of NIMH book.

R-T, Margaret, and the Rats of NIMH, like the preceding volume, Racso and the Rats of NIMH, was written by the daughter of Robert Leslie Carroll Conly (pen name Robert C. Frisby and the Rats of NIMH, continuing the story from the 1986 book Racso and the Rats of NIMH. R-T, Margaret, and the Rats of NIMH is a 1990 children's book by Jane Leslie Conly with illustrations by Leonard Lubin.
