The Sovereign Spring

Cambridge cryptographer Dr. Eliza Thornwood inherits her uncle's Victorian estate in New Zealand's South Island. Inside a hidden room: maps that should not exist. Charts of underground river systems predating modern surveying by centuries. Coded annotations in multiple indigenous and colonial languages. All pointing toward something called the Sovereign Spring.

Maori historian Rawiri Kepa believes the spring is a taonga, a sacred treasure stolen during colonization. A ruthless antiquities syndicate wants it first. Through glacial caves, geothermal valleys, and forgotten goldfields, Eliza and Rawiri race to answer a question the map insists they face: do some discoveries deserve to remain hidden?"