A soldier from the 15th century, a university student from the 19th century and a nurse from the present join the secret 'Department of Time', a secret department within the Spanish government with the ability to travel through time. Their mission is prevent changes in history.

Charting the life of Isabella I of Castile, one of the most important women in Spain’s history, Isabel follows her passionate story from childhood to being crowned Queen. From her political struggles within King Henry IV's court to her wedding to Ferdinand of Aragon, the drama encapsulates the passions, emotions and sacrifices of a woman who refused to just be a figurehead and whose outlook was ahead of her time.