Goa (Blood of the Goddess/Kara Dalkey, 1)

Thomas Chinnery is the young assistant to a Master Apothecary of England. He has been entrusted by his master with a perilous journey into the Portuguese-controlled waters of East Africa and India to establish a direct trade in medicinal herbs.
But the captain of the ship on which Chinnery sails has piracy on his mind. The crew attacks a small, rich ship, capturing it and its passengers, only to be set upon by a Portuguese man-of-war. The English fight off the battleship but are sorely wounded.
Aboard the captured ship are a man and woman fleeing the Portuguese colony city of Goa and its Inquisition. The man is an alchemist; the woman is accused of heresy. And in their possession is a mysterious powder they call the Rasa Mahadevi, the Blood of the Goddess. It kills the living, but it can restore the dead to life.
Thus is Thomas Chinnery set on the path that will lead him through his darkest nightmares into the dungeons of the Inquisition and thence to the heart of ancient India.