The Secret of NIMH

A widowed field mouse must move her family before the spring plow destroys their home, forcing her to seek help from a hidden colony of laboratory-altered rats who share a deeper bond with her late husband than she ever knew.

The Secret of NIMH follows Mrs. Brisby, a gentle field mouse whose young son Timothy is stricken with pneumonia just as the farmer prepares to plow the field that holds their cinder-block home. Unable to move the house without risking the boy’s life, she first visits the eccentric crow Jeremy and then braves the terrifying Great Owl for counsel. The Owl directs her to the rats who live beneath the rose bush, a secretive colony far more advanced than ordinary rodents. Mrs. Brisby learns that these rats escaped from the National Institute of Mental Health after experiments gave them human-level intelligence, the ability to read, and the drive to build their own civilization. Her late husband Jonathan once aided the same rats, a fact that opens doors and places unexpected responsibility on her shoulders. With the help of the kindly mouse Mr. Ages and the leadership of the rat Nicodemus, she begins a desperate plan to save her children before the tractor arrives.

Nicodemus entrusts Mrs. Brisby with a glowing amulet said to respond to courage, while the ambitious rat Jenner schemes against the colony’s plan to leave the farm and live without stealing. Mrs. Brisby is captured by the farmer’s son and briefly caged with the family cat Dragon nearby, forcing the rats into a midnight rescue that reveals both loyalty and betrayal inside their ranks. Once free, she must still activate the rats’ ingenious block-and-tackle system to lift her entire home and move it to safety while Timothy remains too weak to walk. Jenner’s treachery culminates in a violent confrontation that costs lives and tests every alliance Mrs. Brisby has formed. In the final hours she discovers the amulet’s power answers only to selfless love, allowing her to protect her family as the plow bears down. The surviving rats depart for a new life, leaving Mrs. Brisby and her children safe in a home that no longer sits in the path of the blades.