La Prueba de Hierro (The Iron Trial) by Holly Black and Cassandra Clare is the first installment in the Magisterium young adult fantasy series, following 12-year-old Callum Hunt's journey into a dangerous, subterranean magic school. The plot centers on Call's reluctant acceptance into the Magisterium and the revelation that his soul was replaced by the "Enemy of Death". Explore the free fragment of the Spanish PDF provided by PlanetadeLibros . The Iron Trial (Spanish) - Worldbuilders Market