A newly married couple moves into a house. But the bride disappears.

An aging engineer pursues a scheme to build a flying machine at the expense of his family's health. When his daughter falls ill, he enters a flying competition to win money for her treatment, even though his design is dangerously untested.

The young daughter of an army captain missing in action runs away from school and is kidnapped by Parisian lowlifes. When the kidnapper flees to Nice with the child, the kind-hearted employee of one of his accomplices sets off in pursuit.