Froggy dreams of drowning. Just as his nightmare is coming true, he is saved by a ghost boy Tad. But is Tad telling him the truth, and why can Froggy now see back to the past - to 1881, when Sydney was gripped by a smallpox outbreak and the Quarantine Station was full of the stench of death?
With Cassie's help, Tad and Froggy realise they must trust each other in order to find what has been lost for more than one hundred years. Then, perhaps both boys can be set free!