The hundred and twenty marks Emil was carrying represented more than a simple sum of money to him and his family.
His mother had given them to him with visible anxiety, knowing that the trip was a responsibility as well as an adventure.
When the money disappeared, Emil understood immediately that his failure was not just personal but affected his whole family.
He thought about his mother and what she would feel and about his grandmother and what she was expecting and waiting for.
These thoughts, rather than paralyzing him, produced something unexpected and powerful — a completely clear and calm resolve.
He did not know how he would recover the money or whether he would be able to do so with no resources at all.
But he knew with perfect certainty that he was going to try with everything he had before he admitted defeat to anyone.
Emil lost his money and decided to catch the thief himself.

The psychological moment at the center of Emil and the Detectives' opening is worth examining with some care and attention.
Emil has been wronged, is alone, is in an unfamiliar city, and has no practical means of addressing what has been done to him.
In this moment he makes a choice that will determine not only what happens next but what kind of person he is.
He could choose passivity — report to the police, call his family, accept the sympathy of strangers, and go home diminished.
Or he could choose agency — follow the thief, find some way to act, refuse to accept the wrong as the final state of things.
Emil chooses agency, and Kästner presents this choice as natural rather than heroic — as the obvious response of a person with integrity.
What is remarkable is not that Emil decides to pursue the thief but that he decides this before he has any idea how it will work.
The decision precedes the plan, which is precisely the order in which genuine moral commitment always operates in real life.
Emil lost his money and decided to catch the thief himself.