Petre Orsa, a young peasant gets a job at the Hunedoara Steel Mill with the dream of becoming a top-notch steel-man, having Mihai Solca - a sort of communist industrial hero- as his role model. He starts low moving dirt around with a shovel but he soon gets into the team of an old steel man,foreman Tudor Baci. He meets Livia, a crane operator and he goes on a trip with her to the Hunyad Castle, a local attraction. Foreman Tudor Baci gives Petre the chance to pour his first steel bullion and he manages to succeed through very hard struggle. He asks one of the specialists to help him make a nail to have to show his father back at home (that was one of his dreams). Even the communist press gets interested about him and writes a nice article about him and he starts slacking off. He starts having disputes with his foreman, Tudor. Petre tries to get a position in Solca's team but Solca decides he's still too unexperienced. Petre gets upset and he leaves the site. When the loud-speakers are just about to announce the festivities for the two newly opened steel furnaces, Petre returns. Him and the other steel men are all laughing and start dancing around the furnaces. Tudor shows his the "sun like" fire inside the furnace(that's the meaning of the title) while Livia smiles down on him from the crane above