Senator Mon Mothma denounced the Galactic Empire's role in the Ghorman Massacre and resigned from the Imperial Senate. Erskin and members of Gold Squadron accompanied Mon Mothma into hiding on her Taylander shuttle Chandrila Mistress and several Y-wing escorts. With Mon Mothma and her fellow rebels now fugitives, her friend Senator Bail Organa arranged for the group to rendezvous with Phoenix Leader Hera Syndulla and her Spectres in deep space in order to refuel their ships.
After Mothma's freighter docked with Hera's VCX-100 light freighter Ghost, Semaj and Gold Leader Captain Jon Vander boarded the rebel ship. The two met Hera and her crew Garazeb Orrelios, Ezra Bridger, and the astromech droid Chopper. When Ezra asked what cargo they were carrying, Erskin told them they were not allowed aboard due to security conditions. Hera responded by telling them they were welcome aboard her ship. The Ghost then began refueling Mothma's freighter's Y-wing escorts.
While they were refueling, an argument broke out between the pilot Gold Two and the Spectres over secrecy and tactics. When Hera defended her crew, Semaj took a conciliatory stance and remarked that the tactical infiltration pod that the Spectres had encountered earlier was probably looking for them. After an Imperial light cruiser and a Gozanti-class cruiser exited hyperspace and damaged Mothma's ship, Semaj, Mothma, and the remaining crew fled aboard the Ghost. Together with the Y-wing escorts, the rebels then fled to the Archeon Nebula.
Following their escape, Semaj advised the former Senator Mothma to abandon their mission and return to a safe hiding place on Chandrila. Mothma disagreed and said that she would not hide because her presence at the meeting on Dantooine was not optional. Mothma then briefed the rebels about her plan to convene a meeting of the different rebel factions on Dantooine in order to form a Rebel Alliance. After escaping an Imperial trap in the Archeon Nebula, Semaj and his fellow rebels managed to reach Dantooine where Mon Mothma delivered a speech to the assembled rebel fleet.
- "Secret Cargo" (First appearance)