Hayate the Combat Butler Season 4 tells the story of Ayazaki Sa, who was originally studying in a public high school. Because his "excellent" parents were very lazy and irresponsible, he had to work every day to support his family. On Christmas Day of his first year in high school, he found out that his parents owed a debt of 156,840,000 yen, and sold himself to the underworld to pay off the debt. During his escape, Sa happened to meet a girl - the capitalist lady Sanzenin. As a result, due to various misunderstandings, Sanzenin paid off Sa's debt, and Sa became the "debt butler" of Sanzenin's family, and therefore transferred to the aristocratic school Hakuou Academy.