Thirteen year old Felicity Cumberland is accompanying her Uncle, Professor Portland, and his renewable energy machine, the Smoke Engine, to Townsville on the ship YONGALA. Fearing that the Smoke Engine will harm their interests, the Coal Board sends Boer War veteran, Corben Plath, to kill Professor Portland. Onboard YONGALA, Plath plots Portland's demise and  unwittingly develops a friendship with Felicity. Plath's murderous taks is further complicated by four undercover agents tasked with protecting the Professor. As a cyclone bears down on YONGALA Plath finds that his own salvation depends on Felicity surviving the storm.