Night Wind to Bahia — Thomas Thorpe

Without a crew, a clipper ship heads into a violent storm. Helpless to navigate, the Darmon family, survivors of a cholera outbreak, fight for their lives before drifting to the coast of Bahia, where fishermen scuttle their vessel.

On land, the castaways find themselves stranded on the shores of a country struggling for independence. A weak Regency government copes with warring landlords, slave revolts and a cholera epidemic. When escaped slaves abduct the Darmon women, their trail leads to a site of massacre. Arrested and taken to Salvador, they're visited by an emissary who bargains for help with a dangerous blood transfusion experiment to protect the future leader--Dom Pedro II.