A Vampire's Kiss.

Set in the fictional city of Maramores, the plot centers on the character of Lívia, whose destiny begins to be shaped in the 12th century when the vampire Boris falls madly in love with her and decides to win her over at any cost, regardless of time or place. In medieval times, Lívia is Princess Cecília, Beto is Count Rogério, and Boris is Duke Boris. The present-day story begins with the introduction of Lívia's story, her husband Beto, and their children, Zeca, Tetê, and Juninho. The family's happiness will be destroyed, just as in Lívia and Beto's past lives (Princess Cecília and Count Rogério), by the reappearance of the vampire Boris. He wants to reclaim Zeca, who is not actually Lívia and Beto's son, but his son with a mistress. As soon as he was born, while still in the maternity ward, Boris placed Zeca in the place of Lívia's true son.