For a long time the Adrestia Syndicate and the Faerghus Brotherhood had constantly been at war with one another, the Leicester Alliance was able to help them broker a delicate peace treaty between the two families, effectively separating their business. Since then there had been minimal conflict for the families, until one day, Lambert Blaiddyd, the leader of the Faerghus Brotherhood was brutally attacked and killed along with his wife and closest guards. While the incident was immediately pinned on the smaller gang of Duscur and subsequently massacred, Dimitri, Faerghus’s lone survivor of the head family, secretly believes the true perpetrators being the Adrestia Syndicate. 

Fast forward 7 years and Edelgard, Dimitri, and Claude, heirs to the Adrestia Syndicate, Faerghus Brotherhood, and Leicestar Alliance respectively, are students at Garreg Mach, mostly a front school in the shadier part of town for the mob kids and gangsters to learn the tools of the trade. As part of the peace treaty, Garreg Mach is divided into three houses, separating students from the syndicate, brotherhood, and alliance. 

While at the academy, Edelgard secretly is plans to do away with the peace treaty and declare war on the mob as a whole, intending to change organized crime at its core. Meanwhile Dimitri continues to plan his revenge on the Adrestia Syndicate and put an end to the unnecessary killing.  At the same time, Claude hopes to use the Alliance to open the borders between families in Fodlan and outside the country.