Describe the life led by Mumbi during Gikonyo's absence.

Mumbi takes on the responsibility of building a new house and working in the trenches while Gikonyo is away. She refuses food from Karanja when she is starving, but then regrets it, and takes the food he offers her next time. She feeds her parents, Gikonyo's mother, and herself. After the trench is built, she takes a job on a tea plantation, and all her money goes to feed her family and send her brother to school. Mumbi gives in to Karanja only once, in a moment of weakness when she learns that Gikonyo is coming home. She immediately regrets it.