In the frontier village Vetrov boys from the children's home called Indians lead a bitter "war" with the local Símáks. Before a battle the Indians have a meeting in the sandpit with a smoke signaling. The smoke brings to the sandpit a frontier guard Tomás with a police dog Ranek. The children learn from Tomás that Rank served out and that it shall be destroyed. The nine-year old Fanda writes a letter to the "minister of the frontier guards" in which he asks to let Ranek live. To save Ranek's life he also visits the local frontier guard commander. In the end it is decided that children from the children's home may keep Ranek.
Young Jan Stehlík signs up for a job to build a new mine. On the train he meets the pretty Alena, who falls in love with him. However, she means nothing to the superficial Jan, and when the girl becomes his lover, he treats her rudely and insultingly. But Alena's relationship troubles the honest Joseph, who really likes her.
