When Melly's cat Jason brings home a tiny grey animal, she thinks it is a mouse. By Auntie Ruby declares the little creature is a bilby. And the baby bilby is still alive! In nursing her bilby back to health, Melly becomes fascinated by the elusive bilby, a harmless Australian marsupial desperately in need of human friends. She joins forces with a ranger and a scientist building a safe home for bilby's in a national park.