Isabel and her brother Alfonso live happily in Arévalo with their mother Isabel de Portugal, widow of King Juan II of Castile. Together with them, his tutor, and almost father, Don Gonzalo Chacón and his companion, and best friend throughout his life, Beatriz de Bobadilla.However, one bad day they are taken by force to the court of Segovia by order of his brother, King Henry IV, on the occasion of the pregnancy of his wife, Mrs. Juana de Avis. A pregnancy especially yearned after years without getting offspring, which has stoked the rumors about the impotence of the king.Upon arriving in Segovia, Isabel and Alfonso remain under the care of the queen, who despises and fears them at the same time because they constitute a threat to the future of the daughter she is waiting for. The hostile environment of the court, the dissolute life of the courtiers and the continuous political intrigues make them mature quickly. Isabel soon understands that they have become mere pawns for the interests of the powerful, and in this game both her brother and she are in danger.