Having helped fulfill Cyril's long-held wish to improve relations between Sutherland and the Náv Kingdom Black Dragon Knights, Fia's training period finally draws to a close and she is now a knight! Though eager to begin her official duties, she takes an extended leave of absence to visit her elder sister, Oria, at Blackpeak Mountain, as well as her former companion, the black dragon Zavilia. However, she encounters a familiar pair of siblings along the way. What surprises does this unexpected reunion hold?