The Secret of NIMH 2: Timmy to the Rescue

The Secret of NIMHTimmy to the Rescue is a 1998 directtovideo animated film produced by MGM Animation and the sequel to the 1982 animated film The Secret of NIMH. In the film, Timothy Brisby, the youngest son of Jonathan and Mrs. Brisby, goes to Thorn Valley wanting to become a hero like his father. Martin is missing and it is up to Timmy and his partner Jenny to confront him and get the rats back. At Thorn Valley, Timothy learns from a young girl mouse that the mice who were presumed to have been killed during the escape from NIMH are still alive, so he and the rats mount a rescue operation.

The film begins with a prophecy, telling how one of Jonathan and Mrs. Brisbys sons would save Thorn Valley from the secret of NIMH. Timothy is chosen to go but his older brother Martin believes he should have been the one chosen. Martin decides to prove his quality, and goes off to find his own adventure.One day Timmy comes across a female field mouse named Jenny McBride, whose parents were two of the lost eight mice who tried to escape NIMH but were thought to have died. The Thorn Valley council decides it would be too dangerous to save the eight mice, so Jenny and Timmy go alone. They take a hot air balloon, but it is attacked by a hawk and crashes in the forest. ........

Source: Wikipedia