Paul is married, a successful engineer, and a conservative candidate in an upcoming local election. He falls in love with Adriana, a café waitress from Italy. Paul's party is very critical of foreign labour and wants to keep Switzerland to the Swiss. Where Paul falls deeper and deeper into the relationship and is ready to leave his wife, Adriana feels the social pressure growing and has to make her own decision.
Thomas is the 12-year-old son of a millionaire who lives in a big mansion surrounded by woods in France. When his mother dies, his father hires a widowed maid to take care of everything while he is away. The woman brings her only son, Charles, to live with them and, hopefully, be company to lonesome Thomas. The rich boy and the poor one become enemies from the very first encounter. Moved essentially by jealousy and fear, Thomas decides to turn Charles' life into a hell on Earth, especially after their parents eventually fall in love. As the title suggests, he wants to make it clear to the invader who is the lord of the castle.
In this film, Albert is an eccentric inventor of missiles who comes under fire from his investors when his first prototype explodes. Even his sympathetic mistress has her doubts, as Albert lashes out in a verbal tirade condemning those of little faith in his genius.