A young stable boy arrives in Toledo, escaping the horror of the invaders’ barbarities. After his father has been killed and his sisters kidnapped, he sets off in the company of his inseparable steed, Sabba, with only one thought on his mind: revenge. However, his young age and the dangers that come with an incursion into Muslim territory force him to take another route. In Toledo, Diego finds refuge in the stables of a renowned Moorish veterinarian who, after noticing his innate intuition for horses, initiates him into the art of healing. From this moment on, the protagonist begins a series of adventures that see him searching within manuscripts hidden in a Sistine Monastery, participating in a tournament to win the affections of a nobleman, and travelling through the different historical enclaves to meet spies, magicians, fugitives, kings, etc. With all these people he will share adventures, suffer the pain of betrayal and learn the true value of friendship.