This document provides character summaries and themes for the novel "A Grain of Wheat" by Ngugi wa Thiong'o. It describes the main characters including Mugo, who betrayed Kihika and feels guilty; Gikonyo, a businessman married to Mumbi; and Karanja, an opportunist who collaborated with the British. The themes discussed are colonialism and its legacy, the relationship between individuals and community, betrayal, guilt, and redemption.