The residents of a small town are excited when a flaming meteor lands in the hills, until they discover it is the first of many transport devices from Mars bringing an army of invaders invincible to any man-made weapon, even the atomic bomb.
Jerry Mulligan is an exuberant American expatriate in Paris trying to make a reputation as a painter. His friend Adam is a struggling concert pianist who's a long time associate of a famous French singer, Henri Baurel. A lonely society woman, Milo Roberts, takes Jerry under her wing and supports him, but is interested in more than his art.
Inspector Cassin, a renowned Paris detective, departs to the country for a much-needed break. There he falls in love with the innkeeper’s daughter, Nanette, who is already betrothed to a local farmer. On the evening of their engagement party, Nanette and the farmer both disappear. Cassin takes up the case immediately to discover what happened to them and who is responsible.
