Set two years after the events of the Civil War and the unfortunate circumstances surrounding Crossbell, seen in Trails of Cold Steel II and Trails to Azure, Rean Schwarzer becomes an instructor for the newly established Thors Branch Campus located in Leeves. Following the annexation of North Ambria, the Ashen Chevalier contends with managing his matured responsibilities for his dual jobs as a teacher and soldier. However, rumblings of chaos begin to echo throughout the land of Erebonia once more.