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Uli, the smallest boy at a German boarding school, is mocked as a coward, so he climbs a gym ladder in front of the school and jumps holding an open umbrella as a parachute. He breaks his leg, and afterward he is respected. The episode shows that public shame can push someone into reckless, self-harming proof of worth, and that peers only see his courage once he pays for it with injury.
The book argues that courage without cleverness is mischief and cleverness without courage is nonsense. Neither trait produces good action alone. Bravery needs judgment to aim it, and intelligence needs nerve to act on what it knows.
Adults falsely remember childhood as carefree and so dismiss children's grief as minor. The book holds that a child's pain weighs as much as an adult's, whether it is a poor boy unable to afford the fare home for Christmas or an abandoned son. The fix it proposes is for adults to remember their own childhood honestly and take children's troubles at full weight.
The teacher Justus becomes the boys' confidant by acting privately rather than by claiming authority. He secretly gives the poor student Martin his Christmas train fare home, and he forgives rule-breaking once he understands its motive. Seen this way, a mentor's authority comes from visible reliability and shared vulnerability, not from enforcing rules.