Melody Klomp is a12-year-old girl living on a sheep station in drought-stricken Charleville, Queensland. Her passion for the environment, particularly birdlife, has been instilled from a young age during annual visits to the Coorong in South Australia, where her Nanna Bell operates a tour boat named The Isabella. One morning, Melody learns that the drought has had a devastating effect on animal life and tourism on the Coorong, so Nanna Bell is being forced to sell The Isabella. As she tries to work out what she can do to help, a magical thunderstorm passes over the sheep station, turning her into a diamond firetail finch.
In the body of a tiny bird, Melody flies south toward the Coorong following the rivers of the Murray-Darling Basin, encountering many challenging adventures and wonderful Australian bush creatures along the way. Once she reaches the Coorong, Melody works together with the local birds to fight a greedy net fisherman named Bernard Finnegan and his pet osprey, Silverclaw. Finnegan is pressuring Nanna Bell to sell him her boat so he can use it as part of his plan to catch every fish in the Coorong for himself. As part of his cruelty, he intends to kill all the annoying fur seals that keep damaging his nets.
Through her days as a finch, Melody learns more about the animal world than she ever could have as a human. Called to arms by the magical elements of nature, she is compelled to share that knowledge with humanity for the rest of her life, just as Nanna Bell had been doing. It seems that their common passion for the environment is more than a coincidence.