In April 1937, he was part of Ignacio Cardona's cell consisting of Glaucia Acosta, Dwight Adams and several Republican soldiers making their to Barcelona. The group made camp to rest for the night and during the campfire, the group was attacked Republican soldiers who had mistaken them for nationalists.
By May 1937, Miguel and the group had made their way to Barcelona. Both him and Dwight were woken by a commotion which they believed was an intruder. After Glaucia cornered the intruder, they interrogated him who reveals that he is Norbert Clarke, an Assassin sent by the British Brotherhood to asist them. He said that he was responsible for eliminating the entire Templar branch in Talinn in 1936. Convinced, Miguel and the Assassins introduced themselves to him.
The next day, Miguel and the Assassins trained with Norbert, who easily defeated them. They later followed Ignacio to a firefight between anarchists and nationalists. Miguel argued with Dwight as he believed that they should side with the government while Dwight believed that they should side with the anarchists. The two were later interrupted by Ignacio, who had unleashed the Koh-i-Noor which produced blue serpent-like projections. Before Miguel and Dwight were consumed by it, Ignacio managed to resist the artifact and throws it away.
As the Assassins check on him, the group was attacked by the Black Cross Albert Bolden, who targets Norbert. As Miguel and the Assassins fought back, they were unable to prevent Albert from taking Ignacio away.