Showering Sound of Cicadas: Spirits Down the River

Everyone prepares for Fiesta des Lumiéres, which starts to bring bad memories for Filicia, whose comrades were killed in a fierce battle. While wandering in the battlefield with a heavily wounded arm, she falls into a tunnel which was well buried under the ruin of the past civilization, where she finds a corpse of a soldier of the old era. In her illusion, the corpse approaches her, apologise for the war they could not win, which makes life vanish from the sea, while on the ground humanity is falling apart. Then Filicia was rescued by someone named Princess Iliya. The girls later send off paper lanterns in the river and Filicia tells Rio her reason for living. Meanwhile, a priest seems to recognize Rio from somewhere.