Pooh and Mickey's Adventures of The Secret of Nimh is an installment from the 100 Acre Wood series.
Mrs Brisby lives in a cinder block with her children on the Fitzgibbons farm. One day - her son Timothy has a fever. She visits Mr Ages who provides her with some medicine from his laboratory. On her way back home she encounters Jeremy a clumsy but compassionate Crow and she befriended Pooh Bear and Mickey Mouse who helped them escape from Dragon the Cat.
The next day spring plowing begins and though Mrs Brisby Pooh and Mickey are able to stop the tractor they know they must come up with another plan. With the help of Jeremy - they visit the Great Owl a wise creature living in the nearby woods to ask for help. He tells them to visit a mysterious group of Rats who live beneath a rose bush on the farm and ask for Nicodemus.
Mrs Brisby Mickey and Pooh Bear went to the rats home where they are amazed to see their use of electricity and other human technology. they meet Nicodemus the wise and mystical leader of the rats and Justin a kind and friendly rat who is the Captain of the Guards as well as a dark ambitious rat named Jenner.
Mrs Brisby learns that her late husband Jonathan along with the rats and Mr Ages was a part of a series of experiments at a place known as NIMH. Nicodemus gives Mrs Brisby an amulet that gives magical power when its wearer is courageous.
Meanwhile - Pooh and Mickey went to find their friends for help. They told their friends that the Brisby family needs their help.
Later that night - Mrs Brisby puts a drug into Dragon's food dish - but the fitzgibbon's son Billy catches her. While trapped in a bird cage she overhears that NIMH intends to come to the farm to exterminate the rats the next day. Mrs Brisby manages to escape from the cage and runs off to warn Justin.
Meanwhile - the rats and the creatures of the 100 Acre Wood are completing the move during a thundrstorm. They tried to move the brisby home. However Jenner kill Nicodemus. Mrs Brisby arrives and tries to convince the rats that NIMH is coming and they must leave immediately. However Jenner snapped and attacks her. Justin rushes to Mrs Brisby's aid and a Fight between Justin and Jenner rages on. Justin defeated Jenner.
Mrs Brisby suddenly realizes that the house is sinking in the mud it landed in. Despite the best efforts of the rats - they are unable to pull it from the mud. However Mrs Brisby's will to save her children gives power to the amulet which she uses to lift the house out of the mud and move it to safety from the plow.
The next morning - the rats have already gone to Thorn Valley with Justin as their new leader and Timothy has begun to recover. Jeremy also finds Miss Right another clumsy Crow and the two fly away together. Pooh wished that he could see Justin again. Piglet told Pooh that it seems that Justin is having a crush on Mrs Brisby. Pooh told Piglet that "sometimes people cared too much. it is called love".