Leo is a young mouse of Jewish family so similar to Timothy Brisby, but with white hide. His real name is Leandro Valhalla. He was captured by NIMH and put and a cage with the file c4. scientists of NIMH discovered an extraneous ability from Leo. He can to control the metal like a magneto; but He can't to scape of a cage made of crystal.

Timmy was captured too by NIMH, when he was searching to Teresa. He and his sister were without any clothes, for to act like an ordinary rodent captured by those scientist.

Teresa found to Leandro crying in his cage. He was nude and trembling by cold.

Was so good luck!

The help from Cynthia, because she and Martin were here for to braek the Leo's cage.

Tim carried to Leo with mr Ages for a medical examination.

Mr Ages said Leandro has good health, but he was so hungry and tired. Leo asked if he eleder doctro mouse can to need an assistant in his lab, because Leandro's mother was a scientist mouse too.

Mrs Brisby doesn't know if her family can to trust in that young mouse, But when she saw to Leo... She recognized to Leo as her nephew because she found great similarity to Timothy. She said than a year before Timothy sickness. She found a little mouse crying in the forest. That kid was wound in his left eye.

The destiny is some crazy, because that kid ws Leo and Jonathan Brisby saved a young female mouse called Pearl.

She has been the lost half sister of Elizabeth.

Leo was really sad when he knew that sad story. He believed be guilty by Jonathan death.