The Little Stars(1963)

When their children fail to come home, their parents start to worry. Due to their own neglect and unfulfilled promises, the children, Maria and Suzy, are getting some help from an old man, their former teacher, to go to the zoo and other entertainment centers by themselves. When the police are called, the kids are quickly found and returned to the parents, but the teacher is so heavily shaken by this experience that he admits himself to a mental asylum.