While exploring the coastal sand dunes near Goolwa, Patrick McWaid and his siblings encounter a ship breaking up on the rocks. They soon learn it's a boatload of Chinese immigrants headed for the goldfields. In a dangerous rescue, Patrick meets a boy named Jasper who seems to be hiding something. Nevertheless, Patrick vows to help the boy in any way he can.

But the nasty Mr. Li, leader of the immigrant expedition, has a much different plan for Jasper. And negative attitudes in the community make it difficult for the McWaids to assist the Chinese miners. The villagers' unfounded fears of "yellow fever" create panic and threaten the safety of both the immigrants and the McWaids' paddle steamer, the Lady Elisabeth. Stricken by illness himself, can Patrick beat the clock to stop the unthinkable from happening?