'Sergeant Sal'is a cheerful and bossy thirteen-year old, hence the nickname her family have given her. She has crossed the world with her nine-year-old sister Lizzie, on a ticket meant for her eldest brother, planning to take the shop job he has been offered in New Plymouth.

The job doesn't happen. Instead, she finds herself on an adventurous trek through the Taranaki bush, following the party of an English artist who wants to draw and paint the geysers and other thermal wonders of the central North Island. It is 1850. There are no roads and no shops - not what Sal expected. She has nothing to eat, and almost loses her life, before a new friend, Ana, appears just in time.