A year after Marth's victory over the Shadow Dragon Medeus in the War of Shadows, men and women gather at the gates of Altea Castle in the hopes of becoming knights.  Among these is Kris, the player avatar and protagonist. After many days of training, the day for Kris to become a knight finally arrives—only for the ceremony to be cut short as assassins descend upon the castle and make an attempt on Marth's life. Kris's company soon learns that Katarina, a young aspiring tactician they had befriended during their training, was working with the intruders from the start and had let them into the castle.  Though they manage to thwart the assassination attempt, Katarina disappears in the chaos and is nowhere to be found. Marth promotes Kris to a position in his royal guard, and together they set out on a journey to uncover the truth behind Katarina's betrayal.