Railroad engineer Sisif (Severin-Mars) rescues a small orphan, whose name he learns is Norma (Ivy Close), following a disastrous crash.

He raises the little girl as his own, along with his son Elie (Gabriel de Gravone), whose mother died during his birth.

Her greatest joy is time spent with Elie, by now a handsome violin maker, whom she believes to be her natural brother.

Sisif confesses to a wealthy colleague, Hersan (Pierre Magnier), Norma's origin and that he is attracted to her.

An eye injury forces Sisif to abandon the mainline railways, and he goes to work instead on the funicular at Mont Blanc.

Without Hersan, Norma is left penniless, while Sisif's failing sight means that he loses his job.

After sending her out to join in a local festivity, Sisif waits at the window, watching not with his eyes but with his mind.