Oni no Sumika

When their parents die in a car accident, Ayumi is adopted by an aunt and her family while her brother is adopted by an uncle and his family. Ayumi feels unwelcome in her aunt's home and is required to quit school to work in the family business. Her only friends are her aunt, a coworker and the son of a politician. The politician's son has a bright future and Ayumi's cousin has her eye on him with marriage in mind, so she's jealous of Ayumi's friendship with him. Ayumi's troubles increase when she finds her brother is unwelcome in their uncle's home.