Magpie Max begins life in Gum Tree Park, which the magpies call the Kingdom of Albert. Albert is the kingdom's ruthless grand master and Max is his youngest son.

Max goes to Home School where he learns everything a magpie needs to know, but his family life is far from happy. Alice, his only sister, defies their father's authority and is banished from the kingdom. She sets out to find the mythical Great River, the place where Mother Nature's creatures gather to exchange wisdom and knowledge.

Max spends an unhappy winter missing his sister, but come the spring, he too is banished. He decides to go looking for Alice but soon discovers that the world beyond the city is far different to how he imagined.

The story follows Max's adventures as he journeys into Australia's harsher landscapes, following clues on the whereabouts of his sister. Finally, he finds her in circumstances that are contrary to their father's values, but she is content for she has found a purpose in life and no longer wishes to find the Great River.