King of Swords by Amy Kuivalainen

In the year 2210, magic has replaced technology and Venice is once again the center of a powerful empire, but everything is not as serene in the new republic as it seems.

Stella is an unregistered magic-user, and a creator of tarot decks, two things that are illegal when they go together. She’ll do anything to protect her secret, even ignore the attentions of Dom Aladoro.
Dom knows power and what people will do to get it. As the heir of the most prominent shifter family in Venice, and a member of the Council of Ten, his life is one of wealth, privilege, and any woman he wants…except for one that he met by chance at Carnevale and who has spent the last eight months ghosting him.
When Dom stumbles across a fight in the dark streets of San Marco, he has no idea he is about to come face to face with his mystery woman. Stella convinces him to help her search for the missing people but they are going to have to work together, and ignore their growing feelings for each other, if they going to find out who is behind the abductions.
From glittering palazzos to dockside brothels, their search will take them into the dark heart of Venice, where money and power has always made the rules, and the price of life comes cheap to those who are only interested in profit.

Please note, this an adult romance book, containing sex scenes, violence and swearing.