The Princes Set Out is the fifty-second chapter of the Oushitsu Kyoushi Heine manga.
Now that Licht and Bruno have left the palace Kai started having second thoughts about staying in the palace. At the military academy there was a training trip where for a month they will be staying in all kinds of different places while participating in army drills and having combined training lessons. Everyone had to go except for royals who are a special exception and don't have to participate in the training trip. Kai wanted to participate in the trip because he wanted to support his friend Elmer but he was having second thoughts because of Leonhard. With Bruno an Licht gone Leonhard seemed lonely so Kai didn't want to make Leonhard feel even more lonely. When Leonhard learnt that Kai wanted to go to the training trip Leonhard said that he should go.