Venice, 1520. In the shadow of the Doge's Palace, where merchants trade in silk and secrets, Isabella Selwyn practices the most dangerous deception of the Renaissance: she is a woman who dares to map the world. Bound by corsets and convention, Isabella disguises herself as "Isacco," a talented male apprentice, creating nautical charts for explorers seeking fortune in distant lands. Her maps possess an otherworldly precision; they reveal islands that don't exist on any other chart, routes that lead to impossible destinations. When the charismatic merchant Matteo Ricci seeks her expertise for a lucrative expedition, their partnership awakens desires that could destroy them both. But Isabella's gift carries a curse inherited through bloodlines. Her visions, glimpsed in the dark waters of Venetian canals and polished palace mirrors, show fractures in reality itself. The symbols she instinctively draws encode fragments of the Ark Codex, an ancient text that maps the boundaries between worlds. Her sister Clara's ethereal compositions, when merged with Isabella's designs, create something that transcends both art and science, a melody that echoes across time. Brother Lorenzo and his secretive order, the early Whispering Society, hunt for such artefacts. As their investigation closes in, Isabella realises the terrible truth: her family bloodline is destined to chart pathways between paradise and damnation. Every map she creates brings both wonder and catastrophe. Torn between her love for Matteo and her duty to protect future generations, Isabella must make an impossible choice. Her decision will scatter the codex fragments across Mediterranean trade routes, seeding a mystery that will span centuries and continents. The Mapmaker's Daughter weaves Renaissance history with supernatural intrigue, forbidden romance with cosmic consequence, in a story where love transcends death and knowledge comes at the ultimate price.