During the fourth scene Mr. King forces the four miners to exit the gallery with gunfire. He asks briefly about their progress and sends them back in. Tension grows between Frank and Mr. King. María enters on stage out of breath, bringing liquor to Mr. King. They talk about Frank, and María tries to intercede for her son. It is revealed that Mr. King is Frank's biological father. María and King sing together "Perdónalo, taita" ("Forgive Him, Father"), and Mr. King finally agrees not to punish the boy, swayed by the passion he feels towards María. They leave together, while Higinio, María's husband, comes out of the gallery and furiously acknowledges his anger towards his bosses and plots his revenge.