Subplot
The intense subplot of Hideo and Sue shows that such a relationship like that of Amy and Adam can exist for a long period of time. It may be an outlook of their future life. Moreover it demonstrates that "whites" are not naturally prejudiced. It also illustrates how old-fashioned the idea is that women should do housework and men should go to work. Instead of this, Sue and Hideo see each other equal, so both are going to work and share the housework between each other. Hideo usually does the chores requiring more physical strength for and Sue does the remaining work. It is in fact a very idealistic view of people, always being fair and unbiased towards others in trying to understand and help them. There are also many other subplots in the story such as Adam and his mother, and Amy and her father.
Read more about this topic: The War Between The Classes