When the two boys realize that the dog is in fact very tame and friendly, they decide to bring him to the garrison. Suddenly, however, a whistle resounds from somewhere, and the dog runs away. As there is no human being to be seen, the boys are unable to explain the situation. Klaus’ father, however, has an idea what might be behind it.
Little Klaus spends his holidays with his father, the captain of a border garrison, where a legendary marsh dog is rumored to live.
When the two boys realize that the dog is in fact very tame and friendly, they decide to bring him to the garrison. Suddenly, however, a whistle resounds from somewhere, and the dog runs away. As there is no human being to be seen, the boys are unable to explain the situation. Klaus’ father, however, has an idea what might be behind it.