Lulu and Judy Geeson continue their earlier roles and come to the farewell party. Thackeray announces that he is leaving for an inner-city school in Chicago where he will teach again. In Chicago, he meets a former colleague who is the principal of the school. Thackeray learns that there is an A class with good students and an H (for "horror") class for the no-gooders. He convinces the principal to let him take the H class as a History teacher. His new pupils are Hispanic, Black and White kids who are noisy, unruly and engaged in destructive behaviours. Like in London, he starts by teaching them some manners. He addresses them as Mr X or Miss Y, and expects to be called Mr Thackeray or Sir (hence the titles)
　　Little by little he learns their personal stories: Wilsie is a gang leader who protects his younger brother. Another is a black female who battles against double prejudice. The white kid is growing without parents and hides this to avoid being fostered.
　　We also know a bit of Mr Thackeray's story. As a teenager in Guyana, he fell in love with a Chicago girl whose father had come to build a mall. They lost contact and he went to Britain to study, became a teacher and got married. He is now a widower but decided to take this teaching opportunity to find his earlier love.
　　At school he sets out to teach these troubled kids of their true potential if they take their fate in their hands. He teaches about the non-violent resistance of the historic fighters of civil rights. When he discovers Wilsie smuggling a gun into the school, he confronts him and convinces him to yield the gun. Mr Thackeray delivers it to the school policeman as a found object.
　　Later, the police pressures him to give the name of the armed kid, since the gun was involved in a cop killing. He refuses to give up the name of the student and has to leave the school.
　　Meanwhile, one of his pupils has taken a job in a newspaper and decides to investigate on the old Chicago love of Thackeray's. The girl arranges an appointment for him. Thackeray meets the son of his former love in a hospital. His mother is ill. Thackeray learns that she loved him back but her father retained all his letters, because she had gotten pregnant, so that young man he had just met is his son.
　　Thackeray learns that Wilsie is hidden because he thinks that the police are after him. His brother takes Thackeray to the hideaway to explain the real situation and avoid that Wilsie ruins his life. Through courage and talking, the teacher convinces Wilsie to yield his new gun and confronts a rival gang that had come to fight Wilsie. Wilsie and the friend who had got him the gun explain themselves at the precinct.
　　The kids have been doing a "stand in" and force the principal to accept their beloved teacher back.
　　Unlike the British film, there is no infatuation with him among his pupils, but a fellow teacher (Saundra Santiago) admires him.
　　The film ends with the graduation ceremony and dance. Mr Thackeray announces that he is not going back to Britain but staying at Chicago to teach the new generation.
　　--Wikipedia