Young engineer Vondrák is thrilled to be given his first independent assignment. The entrepreneur Podrousek entrusts him with the project for a modern reinforced concrete building. The deadline for completion is far too tight but Vondrák fears he would not be given another chance, and his fiancée's father condition of approving his marriage depends on his employment. Vondrák pays no heed to his friend Cirkl's sensible reservations about the job. He works day and night and completes the plans in the six weeks demanded.