The Secret of NIMH* is the 1982 film based on the book Mrs Frisby and The Rats of NIMH, written by Robert C O'Brien. The film tells the story of the Brisbys, a family of mice1 who must find a way to move their home out of the path of a menacing tractor, but who cannot do so without risking the life of a sick youngster. The characters of the film include:
Mrs Brisby - a widowed single parent struggling with four kids.
Timothy - Mrs Brisby's youngest son, who falls sick with pneumonia and is bedridden.
The Great Owl - advisor to Mrs Brisby, who suggests she goes to see the Rats for help moving her home.
Nicodemus - the leader of the Rats.
Jonathan Brisby - Mrs Brisby's husband, sadly martyred by the farmer's cat.
Jeremy - a crow who befriends Mrs Brisby and provides the film with some comic relief.
The film differs considerably from the book; enough so that they can be considered altogether separate entities. Some of the differences between the two are:
The change in name from Frisby to Brisby.
Jonathan died a year previously in the book; in the movie, he's only just been martyred.
Timothy is not quite as active in the film, and says significantly less.
Everyone in the movie wears clothing.
Some characters from the book are not in the film.
Jeremy appears more frequently in the movie and is now keen on finding 'Miss Right'.
Nicodemus... no, we won't spoil it for you.
There's a sequel to the film entitled The Secret of NIMH 2: Timmy To The Rescue, released in 1998. It's difficult to find in the UK, but from what the Americans have been saying over the Internet, it's probably not worth the trouble of tracking it down.