In 14th-century Barcelona, a serf's determined climb to wealth and freedom incurs the disdain of the noble class and the suspicion of the Inquisition.

The city of Barcelona is in its moment of greatest prosperity: it has grown to the Ribera, the Fishermen's Quarter, where its inhabitants decide to build, with the money of some and the effort of others, the largest Marian temple ever known: Santa María de la Mar. This construction is parallel to the story of Arnau, a child who is saved from the abuses of his feudal lord by his farming father Bernat and together they take refuge in the county capital, where they become citizens and, with it, a free men. Bernat raises his son as best he can, working as a pottery maker and horse groomer, eventually adopting a second son. Famine and uprising brings his death, leaving the young Arnau to raise himself as a stevedore; he eventually finds fame and fortune as a money-changer. A strenuous life, always under the protection of the Cathedral of the Sea, that was going to take from the father the misery of a fugitive to the son's rise in nobility and wealth. But this privileged position gets him envy from his peers, who plot a sordid plot that puts his life in the hands of the Inquisition.